Trying to do the math on an affordable HPA system

I know 'affordable' depends on your wallet, and mine is pretty tight, but Im determined to give this a try if I can. I really need to keep the total cost to under $300 if at all possible - less is more in this case.

I have been reading a gazillion old posts about HPA and AA systems for the last several days. I am most impressed with Atomizers posts and theories on this subject. There seems to be very few people doing HPA and even fewer still doing AA, and many of them don’t seem to like sharing details, or pics and posts in old threads have been deleted or are unavailable any more. So, its been a lot of searching old posts on several forums, and making lots of notes.

Atomizer has convinced me that an AA system would be ‘best’, but I have decided that I am unwilling to spend the $$ on that - for now.

That’s mainly because it would stretch my budget too much for an experiment that I may not stick with long term. Plus, I really don’t have room for even a small air compressor and aux air tank on top of the other items needed.

Its pretty clear that AA, and to a slightly lesser degree HPA, are not for everyone, and I may end up at the end, deciding that it isn’t for me either. I love almost everything about AA except the initial cost, so that leaves HPA. Even that is going to be difficult to do ‘well’ on my budget.

I’m trying to make the math work on an ‘affordable’ HPA system. So that’s goal #1.

#2 is to produce nice fuzzy aero roots. I don’t want to try this unless I have a reasonable chance to get at least fairly decent, fuzzy aero roots. That assumes I can get it dialed in properly with my equipment choices.

#3 is to not kill them all off if I go out of town for a week at a time. The system needs to be able to run for at least 5 days on its own – once its dialed in. That also assumes no parts failures for those 5 days.

#4 is to have a system I can start seeds and/or clones in and take them all the way to harvest without having to move them.

I 'think' I have an idea for a system that will meet all those goals, but I need some help fine tuning the details.

I have two Blue Dream mothers that can supply me with a couple of dozen clones to experiment on. Im willing to kill off all of them, over several months if need be, getting things dialed in. I have plenty of personal meds to last me until well into next year if needed, so it wont kill me to not have a successful harvest for several months at least.

My main questions still revolve around the design of the root chamber, selection, and placement of nozzles, and a host of smaller questions about various other details. My head is still spinning trying to assimilate it all and Im not even close to getting there yet.

In the next few posts, I’ll put up a couple of crude drawings of my proposed system and how the grow tent will be laid out, and a preliminary parts list. Any and all help, advice, etc will be greatly appreciated.

However, don’t waste your time trying to talk me out of this or suggesting I go back to soil, hempy buckets, or what ever. The technical challenges and details really appeal to me, so I really want to play with this no matter how it turns out in the end

Here is a crude flow diagram of what I think would work for me. If I have anything out of place or have forgotten anything important, please feel free to jump in with any advice. corrections or suggestions.

I have left off details like couplings, T’s, shut off valves, and minor parts to drain the accumulator and rez, etc. I also didn’t draw in the pressure gauge. I may go with two – one before and one after the pressure reducer. Im going to need to monitor, and adjust both of those while dialing things in, and two gauges will make that easier. Gauges are one of the cheaper parts. Im also considering one of those inexpensive BluLab dual probe TDS meters to monitor the TDS of the runoff, and the supply water.

From my reading, it seems that there is a close interaction between almost all the parts. Which, and how many heads you choose, for example, depends on the pressure ranges available from the pump and cutoff switch, the root chamber size, and shape, pressure differentials at the reducer, where and how many solenoids, etc etc.

I don’t really fully grasp all the theory behind this, but I think I am kind of, more or less, in the ball park. I’ll post my preliminary parts list later – Im still tweaking it because every time I re-read my notes from old posts, I find some detail I over looked earlier!

@Atomizer

@dstroy

these 2 know what they are talking about

This is my proposed tent layout. My grow tent is in my hobby room, so space is limited. Its 28”deep x 38” wide x 48” tall - inside dimensions. It sits on top of my wood work bench which is 30” above the floor. My current rez, pumps, carbon filters and misc stuff is all under the bench at the moment and most of that will need to move for the new layout.

My current thinking is to cut a 24” round hole in the top of the bench/floor of the tent, and hang a 30 gallon fabric smart pot below the table. The cut-out will have an insulated foam top on it with cutouts for net pots, to start and grow clones or seeds. I will only grow a max of two plants at a time to harvest from hear on – in a SCROG setup. I may start several seeds or clones, and then just keep the two best ones to finish the grow.

This layout will keep the root chamber mostly insulated from hi tent temps and should allow me to keep root chamber temps at no more than the low 70’s at most. I really like Atomizer’s ideas of doing HPA drain to waste as well as his ideas for using a fabric root chamber that can air prune the roots if/when they get to the sides or bottom of the chamber.

The fabric pots I’m looking at are 30 gallon pots 24” in diameter x 16” tall. I can easily make them taller by cutting up, and stitching on another pot, so any height is possible as long as its less than the 30” I have under the table. That means I can have a circular root chamber 24” in diameter, with fabric sides and bottom, that is anywhere from under 30 gallons, up to maybe 50 gallons if need be, for no extra money – the pots come 5 to a bundle. These pots are not quite light proof, so a light shield, that also allows for good air circulation outside the pots, will be necessary. The air circulation will be dry room air for evaporative cooling of the chamber. I already have materials for that and the catch basin.

I am still almost clueless as far as how many heads, where to place them, how to point them, cycle times, etc. Based on several of Atomizers posts, Ive been ‘doing the math’ on spray times, flow rates, chamber volumes, etc, but Im not at all confident I have done it correctly. I’ll post those later. For the moment, I am thinking two No Drip Hypro heads will be about right – maybe – but that is really vague guess work on my part.

Parts list and more later……..

rkymtnman said:

@Atomizer

@dstroy

these 2 know what they are talking about

Click to expand...

Thanks!! I didnt know that worked on this forum

Here is the parts list so far.

The filter: $8

https://www.freshwatersystems.com/p-5873-dmfit-filter-strainer-14-x-14-push-in-200-mesh-60-mic.aspx

The pump: $25

This pump is probably the most controversial thing on the list. It’s a solenoid pump or vibrating pump from an espresso machine. They have enough flow to work and a max pressure of over 200 psi. They can last a long time though, and the price is very appealing. The one grow thread where I found this, it lasted two years before the guy let his rez run dry and melted the pump.

https://www.amazon.com/dp/B00NMNA138/?coliid=IEQ688WQGHOC8&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Check valve: $9

https://www.amazon.com/dp/B00838IOS6/?coliid=I36HJNFLL5FG9C&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Pressure switch to control the Ukla pump: $19

https://www.amazon.com/dp/B00H0GUSJU/?coliid=I33J6QXAARI2CI&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



2 gallon accumulator: $45

https://www.amazon.com/dp/B00IRFW38W/?coliid=I1CO1IP68FX3BS&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Pressure reducer to drop the accumulators 130 psi down to the 80 psi range: $13

https://www.amazon.com/dp/B01M0T5K0I/?coliid=I28K49KVPLUUDM&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Pressure relief valve: $23

https://www.amazon.com/dp/B00CMU14CY/?coliid=IGTEZZL50DS2C&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Solenoids – I plan to use one on each spray head, so I need two of these I think: $15 for two

https://www.amazon.com/dp/B016MP1HX0/?coliid=I122HIH9UKFJ5Y&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Hypro No Drip Spray heads – these are the nicer ones I think: $6 for two

https://www.dultmeier.com/products/0.811.833/9844#



Pressure gauge: $14

https://www.amazon.com/dp/B00VUXD7ZG/?coliid=I3HLN4V30BRDXH&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



Timer – This one does 0.1 second timeing and its simple to use it to operate a solid state relay to drive the solenoids. The programmer and timer cost $23

https://www.amazon.com/dp/B015Z2EQCU/?coliid=I8QSWP6W63833&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it

https://www.amazon.com/dp/B0711M25K9/?coliid=I364LV43ZUIRZ4&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it

The solid state relay: This one is way over kill: $ 13

https://www.amazon.com/dp/B075L5X5CT/?coliid=I1D44DMEVJNYZG&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



I will also need a hand full of ¼” push fit tubing, elbows, couplings and cut off valves. That should all come to less than $20

https://www.amazon.com/dp/B077XH5LCR/?coliid=I2N3H2SZFGPGZT&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



The 30 gallon fabric pots – 5ea : $20

https://www.amazon.com/dp/B00VWU35F4/?coliid=I2FY9SXXFM3NI&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



I would also like one of these HM TDS monitors: $20

https://www.amazon.com/dp/B001EHAZGW/?coliid=ISE6ADZJW3FF3&colid=19CTNL8CVWP6J&psc=0&ref_=lv_ov_lig_dp_it



I think I have all the small misc items I will need to finish it off.

This all totals to - $ 273.00.



If I can make the room for it, I would like to go up to the 5 gallon version of the accumulator. Its only an extra $ 17 and would allow for much lower cycle times on the pump. The smaller one will fit perfectly where I want to put it though….

Heck of a parts list With AA it can be reduced to just a few items, compressor, timer, solenoid(s) and nozzle(s). With 30" of height to work with under the bench, i would find a cheap clean chest freezer for the root chamber. Make sure it has a drain fitted on the front (screw type plug). An stc-1000 set at 21C with 0.3C differential setting will give you a swing of 1C (20.3C-21.3C) or in old money about 1.8F. The one i have is 170L and pulls 160w from the wall when its running. It runs for 5 minutes to drop the internal temp from 21.3c to 21c and then switches off. The thermal flywheel effect continues to drop the temp down to 20.3C. Typically takes about 90 minutes to climb back up to 21.3C with a room temp of 28C so it costs very little to run.

Thanks for jumping in. Unfortunately, that pretty much kills my plan.

It sounds like your now recommending that root the chamber needs to be very tightly controlled as far as temps? Fabric root chambers are a no no now?

For at least 7 months of the year, my grow room temps will be below 21C. Usually closer to 19C. I was actually thinking I might need to rig up a small heater between the light shield and the fabric for really cold days - I already have 3 STC-1000 type controllers. I was also hoping that the evaporative cooling effect of the fabric pots would stretch that some during early fall and late spring. I dont grow when it gets much hotter anyway because I cant control the tent temps well enough without AC in the grow room.

Im not completely sure how to take your comment on my parts list. It sounds like a polite way to say its total crap?

Unless quiet air compressors and AA nozzles have come way down in cost, I cant go that way. Im looking at a minimum of $200 for a quiet compressor and air tank - the two tanks I had in storage are rusted crap. Add on a minimum of $250 or so for a pair of air nozzles - plus timers, solenoids, and misc parts - and then add on a chest freezer.

I appreciate the advice - even though its not what I was hoping to hear. Thanks.

If you are blessed with low growroom temps you`ll be ok. My view hasnt changed from what i posted: With AA and HPA, the chamber depth and root temperature are the most important.
I came up with the fabric chambers for outdoor hpa where there`s no control over the root temp and chest freezers are not a viable optionfor outdoor use The air pruning was a secondary benefit, the primary goal was to keep the root zone cool in blazing sun which it does but it doesnt allow you to dial in a temperature and maintain it within 2 deg F
As you said you have 30" of space under your bench i figured you may want to take advantage of it. A good used chest freezer can usually be had for very little, possibly nothing if your lucky.
I wasnt knocking the parts list, i was simply pointing out the difference in parts count between HPA and AA. I cant comment on the actual parts you listed because i dont use them but fwiw i personally wouldnt rely on a pump that needs mains voltage..The pressure switch is not ideal because it wont allow you to set a 50psi differential which you`ll need for charging the tank from 80psi-130psi. i would recommend an italtechnica pm-12 (if you can find one) which have adjustable differential upto 75psi (eg 60-135psi) its more than up to the task but you may have to pay a little more . A 2 gal accumulator running 80-130psi will give you around 0.7gal of nutes. Be aware that the accumulator capacity stated in specs is nominal, in practice you`ll find its typically 15-18% less. The smallest accumulator i have is 24L (6.34us gal) the actual capacity is 19.66L (5.194 us gal), running 80-140psi it holds 7.6L (2 gal) of nutes.

Ah, I misunderstood. Thanks for clearing that up.

I doubt I can maintain chamber temps that closely with my proposed setup - unless I did use your idea. In my grow tent, with an stc-1000 controlling a small heater and a powered vent to outside cold air, I can get maybe +- 3C at best Im guessing. I was thinking of having the stc hooked up to a small personal heater and a small fan that both blew air into the zone between the fabric pot and the plastic light shield. I think I will need heat more often than cooling during the winter months. In any case, I if I am careful when I grow, I wont have any trouble keeping the temps below 22C 98% of the time, and I never let the room temp drop below about 17C, with an average more like 29C

The freezer idea is a good one. It occurs to me that would also work for cooling a rez in the summer. I might try that if I can find a cheap enough freezer.

Yeah, I understand about the pump, but even a diaphragm pump needs voltage. On the other hand, I already have several hi-end chargers, and possibly even an appropriate relay, so a 12 volt UPS that would run that sort of pump for several hours would not cost me much at all - just the battery itself and some sweat. I may consider that once I get further along. Its much less efficient, but I could also use an inverter in the mean time - if I can find it.

Im not following you on the pressure switch. I was under the impression the one on my list could be dialed up to 150 PSI. I thought I could set it to 130 psi - the max for that accumulator - so the accumulator would stay at 130 all the time. Then the pressure reducer would drop it back down to 80 psi to feed to the heads - or what ever PSI I wanted after experimenting. Do I have the theory wrong?

A quick search is not showing that switch available in the US, but I will keep looking. I could order one from ebay though, so thanks! If I just need one that can be set at, or above 130 PSI, and the one I linked cant, then that should be no problem - even if I cant find the exact one you posted.

Yeah, I was figuring I would be lucky to get 1 gallon of usable capacity on the accumulator. Id love to have the 5 gallon, so I will have to see if I can squeeze a small amount of extra space somewhere that still allows me to get to it for servicing.

A little later Im going to post my calculations for those Hypro spray heads and let you see if Im even in the ball park on my understanding of how this should work

Thanks again!

EDit: I goofed. That switch only goes up to 100 psi, so I need to look again.

Oh - one more thing on the freezer idea - wouldnt that cause the problem of having the roots pile up in over spray water once they reach the bottom? I was really liking the air pruning thing, plus not having the roots revert to hydro roots if they sit in water.

Spray times, volume etc....

In the other thread, you recommended a target spray volume in the range of .02 ml/gallon of chamber early on, up to .06 ml/gallon of root chamber later in the grow.

Assuming that 16” is enough depth for my chamber, that gives me aprox 30 gallons. So I need between .02x30 = .6 ml and .06 x 30 = 1.8 ml per ON cycle.

For those Hypro AFD heads, the lowest volume version looks to be around 1.02 gallons/hour @80 psi, or 3861 ml. 3861 / 3600 = 1.07 ml / second of spray time @80psi.

With a single head that works out to spray times between .56 seconds and 1.7 seconds, so I would be limited to .5 or .6 on the low end.

With two heads, those times would be cut in half. Does that sound correct?

I 'think' it might be better to have at least two spray heads, but that’s gets the shortest time pulse down to .2 or .3 seconds or so. Im not sure that with this setup, even keeping the heads very close to the solenoids, that I will get good spray quality over that short a time scale?

Someone else recommended these No Drip heads. https://www.dripworks.com/superfine-misting-nozzle

The red version is no drip, but its volume is a good bit less = .7 GPH @80 psi. If Im following your theory correctly, that lower volume would let me use longer spray times and/or use more heads to get the same spray volume per pulse.

At .7 gph, it works out to aprox spray times between .8 seconds and 2.5 seconds for a single head, or .4 seconds and 1.3 seconds for two heads.


I have no idea about the relative quality between the two heads. Also, I have not found the opening pressure for either one, but I assume it will be under 80 PSI – or at least no one has mentioned the minimum psi needing to be more than that.

Or – would it be better or worse if I run them at lower psi, say 50, to reduce the flow rate?

Or - would I be better off increasing the chamber volume to be able to use longer spray times and/or higher pressures? By making the chamber taller, I can easily go up to 45-50 gallons total volume.

With a timer that can do .1 second intervals, and a 30 gallon 24” diameter x 16” deep chamber (or more) - what number and arrangement of these heads would you recommend?

My original thought was a minimum of two heads spraying into the chamber in such a way that it creates a circular flow. Maybe 1/3 down from the top? I gather its best if they don’t point directly at the roots.


Thats a lot of questions, and of course, all of that assumes I did the math correctly

Ok, found a new switch that sounds a lot better and the same price shipped = $19

http://www.dwyer-inst.com/Product/Pressure/SinglePressure/Switches/SeriesCXA

Mercoid CXA-S3 Series CXA Water Pump Pressure Switch, NC, 35-150 PSIG

Water pump pressure switch, NC, range 35-150 psig (2.4-10.3 bar),
approx. adj. deadband 30-40 psig (2.1-2.8 bar),
max. pressure 204 psig (14.1 bar).

oh duh! I think I get it now on the pressure switch differential. I need a switch that I can adjust the ON pressure as well as the OFF pressure. The ON pressure has to be above the pressure setting on the reducer - 80 PSI in my example. The pump needs to turn back on before the accumulator drops below 80 psi, or what ever I have the reducer set to. The one I linked above has a max adjustment range of 40 psi, so I would be limited to 80-120 psi on the tank.

Im slow sometimes - especially if I have been partaking of the plant.....

Im having trouble finding a pressure switch thats available in the US, with the same pressure range, and differential as the Italtecnica switch for a reasonable price.

Am I correct in thinking that a smaller differential, like the 40 psi of that switch I linked above, will increase pump ON cycles? I think it would also reduce the usable capacity of the accumulator tank. Any other downsides that Im missing?

I've come up with a good place to mount the larger accumulator tank, so I can go up to the 5 gallon tank.

Larry3215 said:

Here is a crude flow diagram of what I think would work for me. If I have anything out of place or have forgotten anything important, please feel free to jump in with any advice. corrections or suggestions.

I have left off details like couplings, T’s, shut off valves, and minor parts to drain the accumulator and rez, etc. I also didn’t draw in the pressure gauge. I may go with two – one before and one after the pressure reducer. Im going to need to monitor, and adjust both of those while dialing things in, and two gauges will make that easier. Gauges are one of the cheaper parts. Im also considering one of those inexpensive BluLab dual probe TDS meters to monitor the TDS of the runoff, and the supply water.

From my reading, it seems that there is a close interaction between almost all the parts. Which, and how many heads you choose, for example, depends on the pressure ranges available from the pump and cutoff switch, the root chamber size, and shape, pressure differentials at the reducer, where and how many solenoids, etc etc.

I don’t really fully grasp all the theory behind this, but I think I am kind of, more or less, in the ball park. I’ll post my preliminary parts list later – Im still tweaking it because every time I re-read my notes from old posts, I find some detail I over looked earlier!
View attachment 4177473

Click to expand...

You don't need an SSR to control solenoids.

Use power mosfets to switch the solenoids off and on. Much cheaper, and more reliable than a cheap chinese SSR.


basic trigger circuit, same one I use all the time for different projects. You can get TO220 heatsinks and drive huge loads with an N channel mosfet.

https://www.adafruit.com/product/355

I think the solenoid is like 5W or something so you need a heatsink, but not a humongous one.

If you locate your solenoid close to your mist nozzles then you do not have to buy anti-drip nozzles.


Pick one or two tubing sizes so you do not have to buy or make a bunch of adapters.

Get a nice piece of plywood to mount everything on, or shelf or something to keep everything that you might ever need to check on there.

I don't think that espresso machine pump is going to work out long term the way you want it to.

If you want a cheap 5 gallon accumulator:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=5+gallon+ro+storage&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=5+gallon+ro&LH_TitleDesc=0

Just keep in mind that the bladders on the cheap RO storage tanks aren't the best.

Eventually you'll probably want something more robust.

dstroy said:

You don't need an SSR to control solenoids.

Use power mosfets to switch the solenoids off and on. Much cheaper, and more reliable than a cheap chinese SSR.

basic trigger circuit, same one I use all the time for different projects. You can get TO220 heatsinks and drive huge loads with an N channel mosfet.

https://www.adafruit.com/product/355

I think the solenoid is like 5W or something so you need a heatsink, but not a humongous one.

If you locate your solenoid close to your mist nozzles then you do not have to buy anti-drip nozzles.


Pick one or two tubing sizes so you do not have to buy or make a bunch of adapters.

Get a nice piece of plywood to mount everything on, or shelf or something to keep everything that you might ever need to check on there.

I don't think that espresso machine pump is going to work out long term the way you want it to.

If you want a cheap 5 gallon accumulator:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=5+gallon+ro+storage&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=5+gallon+ro&LH_TitleDesc=0

Just keep in mind that the bladders on the cheap RO storage tanks aren't the best.

Eventually you'll probably want something more robust.

Click to expand...

Thanks for jumping in! I Like the mosfet idea a lot!! The reviews on those SSR's are not that great. Ive built some power mosfet circuits for fast charging lithium ion battery packs for my RC hobby. I may even have a few laying around in my junk box, and I know I have the resistors, and heat sinks that will work fine. I doubt I have any schottky's. Its been 10 years or so since I worked with this type of circuit, but Im assuming that the "Pin 5V" is the trigger signal from the timer?

Im planning to keep the heads as close to the solenoids as possible, but I will probably use the no drip nozzles anyway. The cost difference is minor, and it will give me some flexibility/insurance if I need to have some short tubing between the solenoid and the head.

Yeah, that pump might well end up being the weak link. The guy in the thread I got the idea from had his running for 2 years with no trouble - until he let the rez run dry and it melted. I have an extra stc-1000 that I was thinking of using as an anti-melt safety switch. Tape the temp probe to the pump and set the cut off temp to a few degrees above its average running temp.

On the plus side, it saves me about $75 compared to a diaphragm pump - which is enough to pay for the accumulator plus a bit.

That accumulator you linked to is the exact same model I found on Amazon - at the exact same price

Yeah, Im still messing with different plans for how to layout the bits and pieces for easy connections and access for maintenance, monitoring etc. My space is small and multi-purpose, so I have a bunch of juggling to do to get it to fit and be convenient to work on and use.

I just spent some time looking through your grow journal. I may not post any pics of my build - out of pure shame. Your build skills are awesome! I am no where near that neat in my layouts.

Larry3215 said:

Thanks for jumping in! I Like the mosfet idea a lot!! The reviews on those SSR's are not that great. Ive built some power mosfet circuits for fast charging lithium ion battery packs for my RC hobby. I may even have a few laying around in my junk box, and I know I have the resistors, and heat sinks that will work fine. I doubt I have any schottky's. Its been 10 years or so since I worked with this type of circuit, but Im assuming that the "Pin 5V" is the trigger signal from the timer?

Im planning to keep the heads as close to the solenoids as possible, but I will probably use the no drip nozzles anyway. The cost difference is minor, and it will give me some flexibility/insurance if I need to have some short tubing between the solenoid and the head.

Yeah, that pump might well end up being the weak link. The guy in the thread I got the idea from had his running for 2 years with no trouble - until he let the rez run dry and it melted. I have an extra stc-1000 that I was thinking of using as an anti-melt safety switch. Tape the temp probe to the pump and set the cut off temp to a few degrees above its average running temp.

On the plus side, it saves me about $75 compared to a diaphragm pump - which is enough to pay for the accumulator plus a bit.

That accumulator you linked to is the exact same model I found on Amazon - at the exact same price

Yeah, Im still messing with different plans for how to layout the bits and pieces for easy connections and access for maintenance, monitoring etc. My space is small and multi-purpose, so I have a bunch of juggling to do to get it to fit and be convenient to work on and use.

Click to expand...

Yes, the pin is the trigger. If the voltage from the trigger pin is 12v you don’t need a LL mosfet and can get a cheaper one.

The shottky diode is necessary, the solenoids are inductive loads.

Good luck, it’s going to be fun and frustrating.

Larry3215 said:

I just spent some time looking through your grow journal. I may not post any pics of my build - out of pure shame. Your build skills are awesome! I am no where near that neat in my layouts.

Click to expand...

Please share. I do what I can with what I can get my hands on which is a lot sometimes. Get creative and don’t be afraid to share your ideas.

I’m building another controller right now, but for the res this time. My system is recirculating. I’ll share but in another thread.