Backyard Aquaponics
A place to discuss aquaponics

Nice work VB, was that about 24 hours to get back to zero?

AP - PH up is bicarb.

It is not ideal because of sodium content (too much could harm plants) but is good for what I have needed to achieve.

I am intent on pushing the boundaries a bit - so now I know that my ammonia and nitrite are staying within a safe range, even while I battle to increase the PH a bit, I am feeding good quanitities of food to the fish each night (not as much as I could - but a decent quantity all the same).

I know the nitrates are high, but I am prepared to push them higher to see what the tolerance of the perch is. In the past my experience has been that they stop being too interested in the food once the nitrate is too high. At the moment they are still very interested.

Thats the way VB!

The only reason i don't have an abundance of large SP is because i enjoyed pushing the boundaries outside the norm to see how far we can go..............Take one for the team.

Am interested in what NO3 the fish get grumpy at, my SP were at around the 300ppm mark

Love it ...take one for the team

A quick update:

I managed to get the ph back up to about 6.8/7 through gradual addition of bi-carb (ph up). Have maintained a good rate of feeding and have not had ammonia or nitrite creep higher than .25 (reading tonight was 0 on both).

On the weekend I did a water change of sorts. I removed about 200 litres into my duckweed pond and about 150 litres into a container I will be using for DWC once I get my arse into gear.

I replaced the 350-400 litres with tap water (neutralised of course). With removal of this water I of course also removed quite a bit of the bi-carb that was bufferring my system and I also expect the ph of the tap water is on the low side of ph. The result is that tonight the PH is back to 6 or maybe lower. I have added more bicarb - but must get to the prodice shop soon to get a heap more shell grit to put in the system.

It looks like ph is going to be an ongoing battle - particularly if I plan to remove and replace water at all - which was my intention so taht I could utilise some of the nitrogen rich water on my dirt veggie patch.

Who is using lime to raise PH? What type of lime do you use - ie what is it sold as?

BTW - fish are very healthy and always feed very well.

VB check out this site for ph buffering with out sodium problems
http://rps.uvi.edu/AES/Aquaculture/nutrients.html

Aussieponic

I noted that Wilson lennard uses that method too of buffering, adding a little every day, plus the added benefit of added potassium, which we have seemed to conclude is deficient.

just go the JP method! JP, how many pounds of carbonate do you have in your tank again?

Thanks guys - so where does one get potassium hydroxide (KOH) or calcium hydroxide (Ca(OH)2).

28 pounds (12.7kg) of crushed shell in a system of about 125 gallons (500liters)!

My pH has crept up to 7.4, but my bio-load should be kicking in about now to pull it back down.

How about calcium carbonate? I can get this from the produce shop - it is used in horse feed.

Janet - that's a lot of of shell - I just bought 5kg for my system.

From here

This info - also from the same place:



Does anybody know what I should aim for with perch?