Backyard Aquaponics
A place to discuss aquaponics

HI Folks, haven't updated in a while. We have started a new year and have new students. They have started a new blog.

http://mpiaquaponics.blogspot.com/

Our systems seems to be running OK. Certain plants do better than others. The biggest problem we have is that seedlings in one GB aren't doing well. They get some kind of wilt/burn from the gravel and its quite difficult to plant them without getting the stems to touch the gravel. More mature seedling that are stronger do better.

Oh and get this, our ammonia has been high like 5ppm sometimes up to 8. The fish are totally fine. I don't get it. Water is super clean and clear.
Our pH is pretty low too.

Nutes:
Ammonia 4
nitrite 0
nitrate 100
pH 5.5-6

Anyway, what do you guys think?

You're getting away with your ammonia level due to your pH and water temperature...

But your pH needs to be buffered back immediately.... at least to about 6.4...

Using some Potassium BiCarbonate.... or Calcium Carbonate.... will not only buffer the pH... but might help the stem growth/strength....

Calcium Hydroxide, "slaked lime".... or even BiCarbonate of Soda can also be used... be cautious with the use of slaked lime, it's a very strong base...

Placing some shell grit, or oyster shells inline with your wtaer inflow to the sump or growbeds will provide both some Calciium for the plants and some long term slow release buffering...

Your Nitrate level shows that your need lots more plants in your system....

P.S ... be cautious when buffering your system with any of the above.... small amounts and test.... then reapply if needed...

You don't want to alter pH more than 0.4 points at any single stage...

I'll have to look for some calcium bicarb

Rupert, we have 140 gallon ponds. How much baking soda do you think I should add at a time?

i guess this is kinda late, but you can find something like seasol at the nursery by kalhii pets. its $8 a bottle, cold processed seaweed extract.

Thanks hellbent. Found maxicrop on ebay with free shipping. Awesome deal. Stuff is great!

So I got my hands on some calcium hydroxide. How much at a time should i add if I have 140 gallons?

Try a heaped teaspoon... then test your pH after several hours...

If it's moved by 0.2 - 0.4 points... don't add any further for several days... then repeat if required...

Thanks Rupe. Been trying to move pH up. Its stubborn. I might even try having the kids do a partial water change. I've been slowly adding potassium bicarb and calcium hydroxide. pH is still around 5.5 in one tank and just below 6 in the other.

Overall plants are doing very poorly and I have no idea why. i've exhausted my limited knowledge. Getting kind of frustrating. Seedlings are constantly dying or growing very very slowly.

Ack!

If those levels of pH are correct then your bio-conversion is probably inhibited... and not producing the level of nitrates needed for your plants... some of which may also be inhibited by the pH...

Up your dosage (2x) of the slaked lime... and test your pH again... when you get it back to about 6.4... I reckon you'll see the difference in your plant growth...

Thank rupe. will pile in the pot bicarb.

Why is the pH dropping? Is it a side effect of the nitrogen cycle? I think thats what going on right?

I will also get some shell grit from the local feed store. Hopefully that will buffer the system.

If you've already dosed with Potassium BiCarbonate, and you don't currently have any plants ready to flower/fruit/seed... then save it, until you need it...

And use the "slaked"/"hydrated" lime instead... it's also more powerful...

And, yep, your pH drift is due to nitrification...