Aquaponics TDS Question

[G33k Speak]

Is there any differece in using TDS readings when it comes to aquaponics??

I have 4 goldfish and a pleco in a 20 gallon tank and I had supplemented with Botanicare products.
My first TDS reading was 1800+ .

The plants were in veg, and seemed to be doing really well.

Should I keep it at 1800ish unless I see problems???

I was actually suprised at the level being that high- even without supplimental nutes, the 4 or 5 fish seem to be keeping the TDS #'s above 1600, so I'm hesitant to add more fish in the 'traditional' over-stocking method.
If I had 8 fish, would I be running a 3200TDS??

and I saw the UVI study that recommended a pH of 7!!

I've run @ 5.2-5.5 for 18 months with botanicare and didn't even know it- but the plants did great.(no fish- str8 hydro)
anyone running a high pH- like around 7?? I try to stick to 6-6.2.

 

[MrFista]

I run several systems and have fretted the pH in the past...

First, the nutrient levels will only rise as much as you feed your fish. You can slow down the food to slow the nutes or add fish to add them. this 'traditional' overstocking you're talking about - not in my school of learning. I use about 1 - 2 kilo (max) fish per 100 litres. This will do 1/2 - 1 square metre of growroom easy.

Now, pH. Aquaponics naturally drifts down. I've found PH for MJ is ideal in Aquaponics anywhere from 6.0 - 6.6. Be aware that at 6 or below your bacteria are a lot less efficient at processing wastes.

I run a system on 7.2. A system on 6.8. Why? They're buffered that way, probably drift down in a year or two...

Get a few handfuls of shells, mussels, oysters type thing, boil and then put them in your tank. It will take a while but let the pH climb into the ideal range I've spoken about. Once it's sitting up round or over 6.6 remove 90% of the shells. It should remain where you want it after that, this may take months to set up correctly.

Once the water is buffered as hard as you have it, it is very hard to shift. If everything is growing then radical changes would be foolish...

To assist puuling the pH down use rainwater in your changeouts instead of tap for a while - it's softer and allows some leeway for the lime in the shells.

 

[G33k Speak]

Sorry- I forgot to mention I was using R/O water nad adding cal/mag @ 5ml per gallon.

I'm working on the assumption that the fish need at least a certain minimum caloric/nuterien intake, so I feed my fish what they need, and then adjust the 'output' from the fish.

The pH is pretty stable @6.2 except when I add 10%+ R/O water or botanicare nutes.
I have CO2 in the room, which ends up bubbling through the water, resulting in carbonic acid whic also lowers the pH- but overall it seems pretty stable.

I was afraid that pH of 5.5 or lower could kill the good bacteria, so I think 6.0 is the lowest I want to let it go.

 

[MrFista]

RO water sucks for anything organic I'm sorry to say. What is the pH and ppm of your tap water?

 

[MrFista]

Fish get some nutrition through osmoregulation - they take it in through the gills, and water is an important part of this equation, treated water is better than stripped water in this instance, always cautious to remove chlorines.

Rain water is good, but still soft imo, the cal mag and rain water might work very nicely together.

 

[G33k Speak]

tap is 250ish
u fill R/O vending water was 25ish
Spetra Pure R/O is 6.

rainwater's not an option for any # of reasons.

 

[MrFista]

Tap waters bloody high! What's in it, lime?

I reckon half tap half RO will give you a nice starting water that wont shift too much. It's partially about the buffering of water that isn't too soft, partially about the ecosystem, RO water is crap at restoring or establishing anything organic.

 

[MadR1]

RO water is crap at restoring or establishing anything organic.

My plants used to look great back when I was using treated water for my Aquaponics system. I switched to RO and now the new plants look pretty bad though still growing. I thought it was a bug problem, maybe that also.

I was using a product called “Replenish” to restore the GH, guess that’s not enough.

Added %15 treated water yesterday for the water change. A few weeks before the micro-organisms grow and thrive?

My plants are growing they just don’t look pretty like they used to.