Nutrient Reservoir top offs

For those running recirculating Hydro systems are a lot of people topping off with straight water? From the time the reservoir is filled to the time it is dumped and reset what percentage of that time should I be running at full strength? Typically I don't let it go below 600 PPM before dumping and resetting. For a long time I topped off with half or full strength and went longer than 10 days between changes. Optimal? Far from it I think but learning as I go everyday. Running GH Flora series.

Considering whatever media is being used. I'm using sunshine #4 adb. with 1/3 or better #4 perlite.

I used to top it up with a full strength mix (Lucas formula) but that wasn't for me. My plant grew but they had problems. Topping it off with a full strength mix leads to problems IMO. You just don't know what the plant is taking up in large small quantities thereby adding everything back at full strength you can end up with high levels of whatever and end up locking out things. A full rez change is a reset that the plant needs. Just my 2 cents.

THANK YOU for your two cents. I am just trying to get a feel for how other people do things. MORE CENTS PLEASE! I'm running CES in two veg reservoirs and they specifically state top off with straight H2O cause the micro part of the add back doesn't play nice with the already mixed solution. To more of an extent than with adding back with GH flora series micro? I'm Not sure. Anyways for me it's been water for 7ish days then dump, reset. I'm not adding back nutes with the reservoirs on flora series anymore either as of last week. Things have been nevertheless growing more than adequately up to this point. If it was not for looking into the CES nutes I would still be doing charged top offs and knowingly running an unbalanced nutrient solution and NOT knowing to what extent this factor was limiting growth. I Suppose I'm going to slowley find out. "More than adequate" only wets the whistle as to whats REALLY possible is how i think.

I top with 1/2 strength and only change res when certain additives cycle in our out of the grand scheme of things. H&G (I know, I know. But, it works for me) cuts out certain additives at certain points. So, I figure that should mean a change. I use that as a opportunity to flush as well. this equates to 2 changes in 3 months

Straight water for my plants.

I'm starting to be able to answer a lot of the Warped questions I have in my head. I realize my inquiries may seem trivial. I'm just trying to understand the process a little deeper as opposed to just following the instructions. Aside from trial and error, other people's experience is a most valuable tool in helping understand things. Anyone carrying to elaborate a little more please feel free.

I top up to maintain a set EC for that stage of growth. If my res is at 1.0 ec and it drops to .8 ec I add enough back to bring it up to 1.0. It takes a bit of math. You need to know your appx res volume, considering any losses from the beginning. You need to know how each component of your nutes will effect ec. You need to be able to figure out what EC you need to mix to bring the res up to its setpoint.

Example:
I start with 20L @ 1.0 EC. After 2 days is down to 0.8 ec. I estimate they drank 4 L. So I have 16L@ 0.8ec. I'd need to add 16L@ 1.2EC to bring it back to 1.0, (16L@ 0.8ec + 16L @ 1.2ec= 32L@ 1.0)but I'd end up at 32L. I want to stay around 20L. I need to figure out how to mix 4L to get an EC that will average 1.0ec when added to the 0.8ec res. 4L is 1/4 of 16L so we can expect to see a 25% ec change compared to 4L into 4L. So 4L@1.0 ec into 4L 0.8ec would average @ 0.9ec, but 4L@1.0 ec into 16L@0.8 ec will only average 8.25ec. So to go up 2 ec points we need 4L@1.8ec. 4L@1.8 ec into 4L@0.8ec would average out to 1.3 ec. 4L@1.8 into 16L 0.8ec would average to about 1.0 ec.

I measure in liters only, try to keep my res in multiples of 4 (4L, 8L,16L, 40L, etc). Makes the math easier on me. I've mixed and measured all my nutes in 1L of RO water at 1ML/L, 2ML/L, 3ML/L, ETC. to know how they effect ec. I've found it to be fairly linear across nute lines, measure 1ML/L then extrapolate for 2 ML/L, 3ML/L, ETC.

My base nutes add 0.3 ec per ML/L. My CalMag adds 0.25 ec per ML/L. My silica ads .3ec per ML/L. I'd add something like 4ml/L base@ 1.2 ec, 1.0 ml/L CalMag@ 0.25, 1.0 ml/L silica@ 0.3 to get around 1.7ec, I'd then add drops of base nutes to get up to my 1.8ec I need. Adding in more supplements just means you need to know their EC effect to calculate final EC.

Then there's adding JUST nutes to an existing res to bring up ec. I could have just added 0.5 ML/L base nutes to the 16L@0.8ec res, knowing my base raises ec 0.3 per ML/L I could have just added 16ML of base and brought it up to 1.1ec, then dilute down to 1.0 with RO.

Clear as mud, right?

"Clear as mud" you nailed it! Mathmatics, not a place I excel. It's the trade I make to sample my produce.
It is clear to me I need to begin making the switch from ppm thinking to EC. Sorta like standard vs. metric. I should also learn as you said, how much EC each nute component adds to my water in ML/L to have a better overall feel. I can see how this could help me. THANK YOU FOR SHARING! How long do you wait to do a total reset of your rez?

Paraplant said:

"Clear as mud" you nailed it! Mathmatics, not a place I excel. It's the trade I make to sample my produce.
It is clear to me I need to begin making the switch from ppm thinking to EC. Sorta like standard vs. metric. I should also learn as you said, how much EC each nute component adds to my water in ML/L to have a better overall feel. I can see how this could help me. THANK YOU FOR SHARING! How long do you wait to do a total reset of your rez?

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Every 7-10 days in flower. In veg I'll keep adding back for 2-3 weeks before doing a change out. I just watch the plants for any signs of issues during those weeks. When I do a res change I dump it, fill it with plain RO for 5-10mins to dissolve any excessive salts, then dump and new nutes.

I'm thinking this is from the nutes being unbalanced? The rez was not reset for 2 1/2 weeks and just topped off with full strength nutes during veg.

I am definitely no expert though. Any ideas from just these revealing pics anyone?

You're right, in a standard setup about a week and a half is the normal lifespan of a res. I've gotten away with topping up with nutrient solution rather than water, but never for very long. Here's the deal: the bigger the res, the longer it lasts, the more stable it is.

If you were to use a ridiculously oversized res, you could get away with using only that one for the whole middle period of flowering. I'm pretty sure the only difference between early and middle mixes is Flora Blend, and if there's a little Blend in your middle, it's no big deal, they love it. It's a compost tea type product, and quite gentle. Top up with water, as usual. No need to empty and remix until the last week of feeding, basically.

I say, if you want to be lazy like me, at least double the size of your res (if you have the space, quadruple it) and say goodbye to weird, inexplicable nutrient imbalances!

By the way, did they get a flush between veg and flowering? If not, that might have something to do with it. But mostly, I'd say if your res doesn't let you do whatever you want to it, it's too small.

I should have posted this under nutrients.

Thanks for your response. Unfortunately none of my reservoirs are oversized. I may have unknowingly just figured out how far I can push it. 10 days is a nice round number. I'm trying to better be able to associate the more common leaf abnormalities with the minerals involved.

Run off tested normal so I sent em in. Its only the largest of the fan leaves that look so ragged .

To varying degrees some of the leaf petioles are crispy, crunchy (not as in dried up) and snap while others just bend. Usually it's one or the other, but this particular group of girls has both on the same plant. I have always associated crunchy leaf petioles that you can snap off without a fingernail as well fed plants, both good and bad. I have no idea if this is correct or of the minerals that effect this.

What medium? You said sunshine mix 4, is it the coco for hydro? How old are the plants? How big? What EC & PH? Lights? Temp & RH? So many factors could be affecting them. If you're in coco, go ask in the hydro area, idk coco and it had its own unique issues.

The leaf petiole happens regardless of media or grow system. Have you noticed this on any of your girls? As far as the ragged look to the leaves: it began in veg. Medium is sunshine #4 advanced which is basically regular Sunshine number 4 aggregate Plus with Coco Blended in