huge swing in pH, what could be causing this?

[Al B. Fuct]

From what I understand, h2o2 does a pretty decent job of genocide on the algae? Is this true?

I think you've got it sorted. Along with algae, I've seen other pathogens wreak havoc with the pH too; pythium & fusarium in sufficient gloopy quantities seem to do it as well.

Yep, H2O2 is your weapon of choice. Clean out the algae as much as you can and sterilise the water contact surfaces with a spray of 50% H2O2 @ 10-20ml/litre water. Don't get this in your eyes and don't breathe it! Will sting something fierce.

Dose nutes with 50% grade H2O2 @ 1ml/L every 3-4 days, will kill what's there and prevent any future colonisations. Further benefit is that H2O2 will release O2 directly in the rootmass when it breaks down on contact with pathogens and dead organic matter.

 

[slump]

Good deal Al.

Much appreciated sir.

 

[lorenzo08]

From what I understand, h2o2 does a pretty decent job of genocide on the algae? Is this true?

I've been messing with hydroponics for about 2 months now. I had an algae problem for a few days one week, but I cleaned everything and took preventative measures, and never had another problem with it. I add 1-1.6 tsp H2O2 per gallon to the water, as well as 2-3 drops per 5 gallons of algaside stuff from walmart.

I haven't had any problem since then, except last week I noticed something weird.. clumps of something brown in the water, floating around. it looked slimy, but when you get some of it out on your hand, it's not slimy at all, and seems more like dirt or something. it puzzled me, but I think it may just have been dead algae that started to grow between treatments, and turned brown from dieing and the die in the flora nutes.

1tsp H2O2 per gallon is helpful

 

[Florida Girl]

AL-those plants look healthy and green. My problem is that my tap water comes out at 710-760 ppm's so I use R/O water.

I'm right there with you. My tap water is 550+ right out of the tap. I grow indoor / hydro and even with 1/4 strength nutes it drove my PPM WAY over acceptable for my plants. I lost a few plants before I learned what the problem was (when I got my meter). Even with my RO machine... the water is 50-60 PPM after running it through the machine. It's not 0 .... but a huge improvement over the 550+.... and allows me to control the grow a lot better. RO solved my issue

You have municipal water or are you on a bore? I really wonder what's driving your tap ppm to 760. Seen an analysis of your water? If on muni water, you might look on that util's website for recent analyses.

Hey Al... I do get the annual water analysis from my water company... and I try to read it... but in all honesty I don't understand all the details or what percentages of what are harmful. Suffice it to say... I live in FL and our water here is shit out of the tap. Even my outdoor veggie garden ... in store bought soil doesn't do well with the water from the hose.


I'm not trying to argue for or against RO water.... just saying... some of us really don't have a choice if we want our plants to grow well simply because of where we live.

 

[platypusmann]

I use RO water, because in my area I have water with alot of carbonate.....after 3 feedings my rockwool was starting to turn white from my tap water. I have a breakdown of a sample now, and I can't see that there is anything to interfere with my plants, so I just may switch to tap..I dunno. I have heard that there is need for Mag-Cal if you are using tap....is this true??? Also, I wonder since I have sort of hard water, if I should switch to hard Water nutes??
Anyway...here is my tap water readings:
Barium-.199 ppm
Chromium-2.4 ppB
Nitrate+Nitrite (as N)-.55 ppm
Selenium-5.99 ppB
Copper-.00829 ppm
Lead-1.19 ppB
Alkalinity-241 ppm
Calcium-82.2 ppm
Chloride-12.8
Carbonate-270 ppm
Iron-.0256 ppm
Magnesium-21.4 ppm
Manganese-.00195 ppm
Nickel-.00123
Potassium-1.55 ppm
Sodium-6.35 ppm
Sulfate-18.2 ppm
Zinc-.0363
TDS-291
pH-7.81

SO...anyone have any input....should I switch to this tap, or should I keep buying my RO at 33 cents a gallon??? And if I switch, should I start adding Cal-Mag and using hard water nutes??? Also, I use Advanced Nutrients, and from my understannding they are formulated for RO, so if I switch to tap, can I still use AN, as they offer no Hard Water nutes I can find.

 

[Al B. Fuct]

2-3 drops per 5 gallons of algaside stuff from walmart.

I would not use any algaecides in your hydro system unless it is noted on the label that it will kill algae without killing other plants as well. Remember, algae is a plant, too. H2O2 is useful in that it will kill simple organisms & spores without disturbing vascular plants.

Hey Al... I do get the annual water analysis from my water company... and I try to read it... but in all honesty I don't understand all the details or what percentages of what are harmful.

The evil you're mainly looking for is a high sodium/salinity content. Plants can cope with pretty much everything else.

 

[platypusmann]

The evil you're mainly looking for is a high sodium/salinity content. Plants can cope with pretty much everything else.

How high??

 

[lorenzo08]

I would not use any algaecides in your hydro system unless it is noted on the label that it will kill algae without killing other plants as well.

walmart sells it for use in water gardens. it shouldn't harm other plants or fish. I keep a close eye on my plants, I'll stop using it if I think it's causing any problems. once I get my res temp down where I want it, I'll try going without the algaecide for a few weeks and see if I have any problems.

 

[Al B. Fuct]

I use RO water, because in my area I have water with alot of carbonate.....after 3 feedings my rockwool was starting to turn white from my tap water. I have a breakdown of a sample now, and I can't see that there is anything to interfere with my plants, so I just may switch to tap..I dunno.

I can't see anything evil either.

I have heard that there is need for Mag-Cal if you are using tap....is this true???

Nope, other way around, if anything. Tapwater will contain Ca & Mg while RO removes them. Most of your Ca & Mg will be supplied by your nutes, though. The amts in mixed nutes owing to the content in tapwater is pretty small by proportion.

Also, I wonder since I have sort of hard water, if I should switch to hard Water nutes??

I can't see the benefit if the plants can make use of the dissolved Ca & Mg anyway.

Only high sodium contents concern me. Yours is 6.35 ppm or 6.35mg/L. Drinking water with less than 5mg/L is considered sodium free, so your water has 'very low' sodium.

Also, I use Advanced Nutrients, and from my understannding they are formulated for RO, so if I switch to tap, can I still use AN, as they offer no Hard Water nutes I can find.

See if you can find some documentation from the nute maker which says it is formulated for RO rather than something you may have heard; pays to be certain. The difference would be that things removed by RO would be replaced by the nutes.

 

[Al B. Fuct]

walmart sells it for use in water gardens. it shouldn't harm other plants or fish.

If that's what it says, it ought to be OK.

 

[Florida Girl]

The evil you're mainly looking for is a high sodium/salinity content. Plants can cope with pretty much everything else.

I just dug out the water report. For my county the Sodium detected results are 130 PPM To give a comparison... a few counties over their Sodium reading is showing at 6.7 PPM.

The note in the "likely source of contamination" column says "Salt water intrusion, leaching from soil". I guess it's not surprising considering I live right on the Gulf of Mexico.

RO was the only way to go for me. I think I'll use it on my outdoor veggie plants next year too because they did HORRIBLE this year. My tomatoes and bell peppers all were the size of walnuts and the plants looked sickly from day one.

 

[Al B. Fuct]

FG, you're quite right to use RO when your tapwater is at 130ppm sodium content. The damage to your veggies sounds characteristic of high salinity.

 

[Florida Girl]

FG, you're quite right to use RO when your tapwater is at 130ppm sodium content. The damage to your veggies sounds characteristic of high salinity.

Thanks Al. I guess there are always trade offs.... I have the beautiful Gulf right outside my door.... but shitty water out of the faucet. Also.... the salt in the air is brutal on vehicles. I'd actually sell my house and move inland a bit if the RE market wasn't in the crapper right now.

 

[Al B. Fuct]

FG, we have similar problems. I'm kinda coastal as well. My cars rust out along the roofline, along the rain gutters, usually near the ends of the gutters. That's where I'd expect salt from sea mist that lands on the car to accumulate. The salt spray also trashes uncoated aluminium surfaces like the fork sliders on my motorcycles.

Natcherly, that kind of minor damage beats the crap out of fenders and floorboards destroyed by salt used to remove ice and snow. I lived with freezing winters in the US for 30 odd years. Haven't seen snow in more than a decade now and I don't miss it a bit. Funny, that.

 

[Al B. Fuct]

Quote:
Originally Posted by Al B. Fuct
The evil you're mainly looking for is a high sodium/salinity content. Plants can cope with pretty much everything else.

How high??

Lower is gooder of course, but I wouldn't stress too much about as much as 50ppm if you're using disposable media, where accumulation of salt over long periods of time will not be a prob. The media goes in the rubbish along with any accumulated salt. Your garden patch is another story. You'll use that soil for many years and 50-100ppm sodium in tapwater will definitely make its mark in a few years.

The South Australian govt's Waterwatch website says this:

Table 2 - What does your salinity level mean?

Range mg/l or ppm

Range EC uS/cm (mS/cm x 1000)

Score

Explanation
approx.
0 - 480

0 - 800

Very Low for SA freshwater sites

Range for rainwater and tap water. Good drinking water for people and suitable for animals and plants.
approx. 480 - 1500

801 - 2500

Low to Medium salinity level, for most flowing freshwater environments in SA

A healthy level for most aquatic invertebrates and plants. People can drink water in this range, but it would start to taste very salty. Some plants such as peas, apricots and grapes cannot be grown with water over 1500uS/cm
approx. 1500 - 6000

2500 - 10,000

Medium to High salinity level for freshwater sites in SA, depending on location of site.

Medium to High salinity level for freshwater sites in SA, depending on location of site.
approx. 6000 - 28,000

10,000 - 50,000

High to Very High salinity level for freshwater sites in SA, depending on location of site.

Most freshwater animals and plants will die. Not suitable for poultry, pigs or lactating animals, but beef cattle can use water up to 17,000uS/cm, and adult sheep on dry feed can tolerate up to 23,000uS/cm. Sea water is 50,000uS/cm. Some specialised aquatic species can tolerate high salinity levels, e.g. in estuarine environments.
approx. 28,000 - 42,000

50,000 - 70,000

Extreme salinity levels

Same as seawater or hyper saline. Some specialised aquatic species and marine species can tolerate such extreme salinity levels.

Note that they class water with as much as 480ppm as 'low sodium.' I'd call that pretty salty!

 

[Al B. Fuct]

Lower is gooder of course, but I wouldn't stress too much about as much as 50ppm if you're using disposable media, where accumulation of salt over long periods of time will not be a prob.

Did I say 50ppm for disposable media? Could be higher, 150ppm should be OK.

150ppm sodium water used in your garden patch out back would be another story over the course of a few years, as poor FloridaGirl has found.

If you do get high salinity in your garden bed soil, there's a couple ways of dealing with it. You can grow a crop or two of salt-loving plants (disposing of the veg matter offsite instead of composting as the salt is taken up by the plants), flush the soil with copious quantities of water until the runoff is the same ppm as the water used to flush, or simply dig the bed out and haul the soil away and truck in new soil.

Farmers who irrigate large tracts of land in arid areas don't have it so easy and global warming's going to make it a lot worse. Farmers can't possibly change out their soil and the quantity of water required to flush out their fields would be totally impractical. Some Aus farmers are trying the saltbush cropping route. The saltbush can be used as an animal feed and the salt leaves with the plant material.

 

[corral hollow kid]

I think you've got it sorted. Along with algae, I've seen other pathogens wreak havoc with the pH too; pythium & fusarium in sufficient gloopy quantities seem to do it as well.

Yep, H2O2 is your weapon of choice. Clean out the algae as much as you can and sterilise the water contact surfaces with a spray of 50% H2O2 @ 10-20ml/litre water. Don't get this in your eyes and don't breathe it! Will sting something fierce.

Dose nutes with 50% grade H2O2 @ 1ml/L every 3-4 days, will kill what's there and prevent any future colonisations. Further benefit is that H2O2 will release O2 directly in the rootmass when it breaks down on contact with pathogens and dead organic matter.

Ok...how much H2O2 would go into lets say 50 gallons of H2O?

Thanks!

 

[Al B. Fuct]

Ok...how much H2O2 would go into lets say 50 gallons of H2O?

Thanks!

Make friends with the metric system! It's much much easier to use litres and millilitres than gallons & ounces. The teaspoon measure is OK for cooking but is not standardised worldwide and varies even between the US, UK & Australia. Missing from the imperial system is a convenient and accurate small measure. 1 ml is 0.0338140227 US fluid ounces... see what I mean?

I usually specify:

Dose nutes with 50% grade H2O2 @ 1ml/L every 3-4 days

A US gallon is 3.78 litres, so dose at 3.78ml/gallon.

10ml & 60ml irrigation syringes (without needle) are common and available at pharmacies and usually also at your local hydro shop.

 

[lorenzo08]

I use about 5ml/gallon twice a week of 5% H2O2. is that enough? if I figure it right, I would need 37ml/gallon of 5% to get to the same strength. seems like a lot.

 

[Al B. Fuct]

I use about 5ml/gallon twice a week of 5% H2O2. is that enough?

Nope!

if I figure it right, I would need 37ml/gallon of 5% to get to the same strength. seems like a lot.

Your calculation is absolutely right! This is why weak pharmacy grade (usually 3%) H2O2 isn't much use in a grow op.