Backyard Aquaponics
A place to discuss aquaponics

Our new system is a 2000 gallon cement tank coated with rubber. It originally contained 1300 fry but now we are down to 900. We are putting coco peat in cups which should have lowered pH level. We put a lime in one of the cups that brought the pH level from an 8 down to a 7.6 but after removing the lime it went back up. I considered that the water could have been contaminated but the fry are always hungry. (I was told symptoms of a sick fish is loss of an appetite). I think the next step should be to purchased a better water testing kit. Does anyone have any advice as to which kit I should buy? What about other ideas to how i could bring down the pH level?

I am the newest member of the team and responsible for collecting information off forums. Any feedback would be greatly appreciated!

I'm not sure what you're using but this is what most people get for home systems - http://www.amazon.com/API-Freshwater-Master-Test-Kit/dp/B000255NCI

Lime and lemon juice isn't a good thing to use to buffer your PH. It has anti bacterial properties, which isn't good news for your bacteria. I'm not sure if the levels are high enough once diluted, but there are better things to use.

Have a look for hydrochloric acid, the stuff that's used to adjust pool PH. It's very strong, so only treat the top up water, and do it gradually.

However, if your system is quite new, you might not need to do much to it, it'll come down naturally as the fish start pooping more, and the bacteria starts converting more. You'll only need to adjust it if something is keeping it up, ie, high carbonate levels in the water, media that has limestone in it, or something similar.

Thank you for the advice! We haven't tried hydrochloric acid yet. I will pass on the advice to the team.

Thanks for the link!

Muriatic acid is the same thing as hydrochloric acid. It's sold at home improvement stores to clean masonry. Treat your top off water to pH 6, then add it slowly to your system until you achieve the pH you want. I wouldn't move it more than 0.1 - 0.2 per day or two though to get the fish acclimated to the pH change.

Great idea! Thank you for the advice!

I would bet that you did not lose 400 fry from having a pH of 8 if I am understanding your concern correctly. At one time I dabbled with the hydrochloric acid to try lowering pH but I find that there really is no need to touch your pH. You might just end up hurting your system. The nitrifying bacteria are very efficient animals in which will naturally lower your pH over time. For example, one system I had started with a pH of 8.4 three months later it was at 7.4. Pretty awesome, especially considering I did nothing to try tweaking the pH for that system.

Hi

I wouldn't stress about the high pH levels. I run a site where aquaponics users keep on-line diaries and many of the new starters have pH levels of around 8 with no fish deaths and good plant growth. Once its been running a number of months you will probably find its gone down and if not then you can look at doing something about it.

If you want to keep the diary too, its at http://www.ourresearch.net If you join you can also get access to the other diaries on the system so that you can learn from what others are doing.

Ria

Thank you so much! I appreciate the advice and am checking out the link now.

That makes me feel better about it, thank you. I am still just having trouble figuring out what exactly is killing the fish. Granted i am in the Dominican Republic where the water isn't clean to begin with but it is carbon filtered.