Nutrient Salts falling out of solution in reservoir!

stinkydinky · Oct 21, 2017

hey!

running a drip system out of a 100Ltr rezervoir that is premixed and let alone for a couple of days out of neccessity.

all plants consume rougly 12Ltrs per day so the drip pump is on a timer to cater to those needs.

it is not recirculating so nothing enters the rez its just pumped out on a timer.

a bubble stone is in there aswell.

anyway, after a day or two clearly visible the nutrient salts begin to fall out of solution and after three days visible salts have accumulated at the bottom and get more and more, so clearly fall out of solution.

how to prevent this?

RB56 · Oct 21, 2017

EC drops when this happens?

stinkydinky · Oct 21, 2017

RB56 said:
EC drops when this happens?

i do not know but actually SEEING the salts at the bottom of the rez clearly tells me that the ec must drop
as the solids accumulate at the bottom and do not stay in solution hence it must drop as far as my logic goes.

i have no measurements though as i do not possess such testing units.

HqFarms · Oct 21, 2017

What brand nutes do you use. Some nutes just don't work in a res

stinkydinky · Oct 21, 2017

HqFarms said:
What brand nutes do you use. Some nutes just don't work in a res

i have used the HESI brand nutrients. they are designed for soil and i am using soil - no idea about their stability in the rez.

if you guys got a different suggestion for nutes for use in soil in the rez please shoot

stinkydinky · Oct 21, 2017

cleaning rez today and though i would give a different brand of nutes a go, just to see if it is a different story as suggested above - you never know.

CANNA TERRA FLORES is carried by the growshop around the corner, guess ill go pick up a bottle

Easy7 · Oct 21, 2017

You mentioned in other threads the room is cold. What is the res temp?

Avenger · Oct 21, 2017

remove the air pump and bubble stone

stinkydinky · Oct 21, 2017

Avenger said:
remove the air pump and bubble stone

oh wow that is the first time i hear this, why? everyone seems to say it is a must!

Douglas.Curtis · Oct 21, 2017

You have no way to check ec... you're checking/adjusting pH, correct? Simply adding nutes, without a pH up, will produce a VERY low pH solution, which will cause lockouts and precipitates...

Only Ornamental · Oct 21, 2017

I recently ordered a "pen" like THAT one and am still awaiting delivery... dunno if it's worth anything... Anyway, you might want to get something like that too. There are also a bunch of smaller ones (many brands, nearly identical appearance) for either EC or pH which cost each around € 20.-.

I made the observation that some liquid fertilisers for garden veggies/ornamentals form precipitates within minutes when used with tap water even without pH adjustment (pH up). It wasn't always the cheaper ones which did this. Couldn't figure out the why from the limited composition given on the bottles. Meaning, the more information you can gather and obviously share with the IC community the higher your chances of figuring out what's going on.
Do you add anything else (such as potassium silicate or epsom salt) or is it just a 1 or 2 part liquid/solid fertiliser? Tap or RO water? Ammonia and/or calcium/magnesium inside? Which kind of phosphate? Chelated micros? Which colour has the precipitate and is it amorphous or crystalline? Does the precipitate dissolve in hot water? The nutrient rez is at final concentration and not a concentrate you use besides a second watering rez, correct? Questions upon questions....

Bubbling air through your rez slowly introduces CO2 which A) lowers pH (if I'm not mistaken, this alone shouldn't lead to precipitates such as struvite) and B) results in formation of insoluble carbonates (which often readily dissolve when adding pH down).

RB56 · Oct 21, 2017

stinkydinky said:
i do not know but actually SEEING the salts at the bottom of the rez clearly tells me that the ec must drop
as the solids accumulate at the bottom and do not stay in solution hence it must drop as far as my logic goes.

i have no measurements though as i do not possess such testing units.

Not certain seeing solids at the bottom rules out any possibility of chemical reactions in components other than the fertilizer.. I don't know anything about using nutrient mixtures with soil but it's going to be hard to solve the problem without being able to measure the concentration of your solution. Do you know what's in your water to start? Changes in temperature can have an impact.

BillFarthing · Oct 25, 2017

Air stones cause pH fluctuation. I just use a tiny stir pump.

If you are using additives, keep in mind that humates, silica and chitosan don't play well together.

Douglas.Curtis · Oct 25, 2017

BillFarthing said:
Air stones cause pH fluctuation

Actually, too much air causes pH fluctuations. Your airstones should be inert, stay away from the cheapies.

stinkydinky · Oct 29, 2017

HOLY christ so guys .. i got myself a PH meter and all that AND dropped the airstone and listen to this...

TAP ph roughly 7.4 .. when mixed with nutes as advised roughly 6.8 .. ok, dropped the airstone and let it sit

no more fallouts, no more nothing ! how could the oxygen from the airstone cause that???

Douglas.Curtis · Oct 29, 2017

stinkydinky said:
HOLY christ so guys .. i got myself a PH meter and all that AND dropped the airstone and listen to this...

TAP ph roughly 7.4 .. when mixed with nutes as advised roughly 6.8 .. ok, dropped the airstone and let it sit

no more fallouts, no more nothing ! how could the oxygen from the airstone cause that???

6.8 will not cause any precipitate on it's own, the solution needs to be around 4 or lower for it to happen quickly.

What you're probably seeing is a reaction between the airstone air and whatever is in your tap water.

stinkydinky · Oct 30, 2017

crazy - yet interesting!

RB56 · Oct 30, 2017

stinkydinky said:
HOLY christ so guys .. i got myself a PH meter and all that AND dropped the airstone and listen to this...

TAP ph roughly 7.4 .. when mixed with nutes as advised roughly 6.8 .. ok, dropped the airstone and let it sit

no more fallouts, no more nothing ! how could the oxygen from the airstone cause that???

Could just be time - pH of my solutions changes for 24 hours after mixing, air stone or not.

Avenger · Oct 30, 2017

The nutrient solution pH impacts solubility of nutrients. In the case of iron, high pH (such as > 6.5) reduces availability of iron through the joint processes of oxidation (whereby Fe2+ increasingly converts to the form Fe3+, which is less available to roots) and precipitation (whereby Fe combines with another ion, for example carbonate CO3 2- or phosphate HPO4 2-, and forms an insoluble complex).

bubbling air through (aerating) the solution increases the dissolved oxygen content of the water, increasing the rate of iron and manganese oxidation. It also degases the carbon dioxide which causes the pH to increase. Iron, Manganese, Phosphates, calcium and magnesium all become more susceptible to precipitation as the pH rises above and beyond 6.5pH.

Not to mention the dust and other contaminants you are introducing to the solution through the aeration pump.

The Ph Factor in Hydroponics, Dr.Lynette Morgan

Vanilla Phoenix · Oct 30, 2017

I quit using an air stone a while ago and now my pH has never been more stable. No circulation pump either. I just give it a stir then check pH right before I water with a wand. If I was using some sorta drip system I would use a circulation pump. I'm using PBP Soil with Calmag fwiw.

Nutrient Salts falling out of solution in reservoir!

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