Backyard Aquaponics
A place to discuss aquaponics

I have a new system that I need to add water to frequently, but the tank has a Ph of 8 and I have had afew gold fish die fromt his. This also maybe why my plants are not growing as I hoped. I decided to just keep on adding fresh water since I thought it was the concrete that is leching out the chemicals. It never went down even when I tested right after adding fresh water from the hose.
I am from texas and live out in the country where we have alot of limestone. I tested the well water and turns out the Ph is even higher in there. Is there anything natural, or around the house, ie. crushed shells, rocks, ect. that is very acidic. I thought about pumping water from the lake or capturing rain water since both of those are in safe ranges. Preferably something I dont have to continue to buy weekly.

Any thoughts?

as your system cycles the ph will drop markedly, abd stabalise about 3-6 months down the track. You could add lime or lemon juice, but IMO that's a waste of time. Hydrocloric acid is also used commonly to lower ph

isnt lime on the basidic side of the ph scale? Thats what I thought. I have to add the water weekly so I do not think it will go down naturaly since the water is already acidic.

I think FB was referring to lime juice...

Firstly a pH of 8 is not really high, and should not have kill your goldfishes... did you acclimatise the fishes before releasing them into your tank??

Well FB is right as your system matures, and with a constant supply of ammonia, the nitrification process will naturally make the water more acidic... and yes topping up the tank with higher pH water would somewhat big the pH back up again... not a bad thing if your system is mature, since some of us are actually adding lime to bring the pH back up above 6.

If you are concerned about killing more fishes, you can try fishless cycling. There should be a thread on how to do it in the Useful Info section.

And yes, don't plan on having good plant growth until your system is cycled and your pH is at a good level... pH of 8 is high for the plants since it blocks out lots of the nutrients...

Hi theguy...

We have the same prob since we started and have averaged 8.2 - 8.4. We have added Iron each week at 1 spoonful to each 1000L as advised as the high Ph locks out iron takeup by the plants. we also add seasol... our plants and fish seem to be doing really well even with the high Ph. Just added in rainwater in the last few days and our Ph has dropped below 8 for the first time in I cant remember! Were worried about the high Ph at the start but not so stressed now we are seeing good growth.

Are your plants yellow? If so it might be worth adding some Iron.

I agree with freoboy... dont worry about trying to adjust your Ph as your system will turn acidic over time and lower the Ph by itself which is heaps better for the fish than a quick artificial fluctuation which is hard to maintain especially if you are adding water all the time anyway.


The goldfish dying may have just been from a new system that hadnt cycled yet... what were your water tests showing when you lost the fish?

PS: just read your post... garden lime is alkaline - and also a water hardener... If your well water is already hard I wouldnt add it... but even when you have high Ph its used if your water is too soft (ie: when using rainwater) as its better for fish health. Even with our high Ph we added a heap as we had a lot of rainwater in the system... hope that helps and ive got it all right

The system was pretty much cycled when I added the goldfish. I had minnows bought at the bait shop in the beginning since they were cheap and local. once I felt it was safe to add the prefered fish, I bought 20 goldfish and 6-7 have died but none of the minnows. I tested the water frequently, and the only thing I saw out of balance was the ph.

The only other thing that might be killing the gold fish is alkilinity being high, but wouldnt that be the same as ph? On my 5 in 1 testing kit it has a test for ph and a test for alkilinity as well as the other 3
The plant's leafs are not yellow, but a very light green in the Turnip greens and lettuce.
I'll probably leave it alone for now until everything falls into place since this is a realatively new system and I am tweeking it everyday. Although the ph is high I am still seeing some nice plant growth.

Also one more thing, I have some seedling tomatoe plants in the grow bed as kinda a tester. i bought 6 5-8 inch full plants with thick stems ( adults compared to my little sprouts) would you wait to add these to the beds until everything starts equalizing? I want them to get use to the system with out soil,but I dont want to risk loseing them either.

I wouldnt worry about your tomato's needing to aclimatise to a soilless life... they will love it! Once you have the nutrient levels up enough to sustain the plant growth just chuck them in. Personally we through as much as we could in and didnt worry - because we were fishless cycling we were adding heaps of Seasol, Iron and Charlie Carp (fish emulsion) so plants were doing really well for a new system. I would put them in, and if you think they need a boost down the track, adding a bit of seasol will work wonders IMO.

Strangely enough, you'll find quite a few APers that reckon goldfish are 'piss weak' and quite easy to kill... I bought 6 and now have 4, one with suicidal tendencies, and one that was definitely sick... They may not have been very healthy or in the best of conditions before you bought them anyway if being sold at a bait shop...


If its an AVI? test kit, you may find there is a Ph and a High Ph test... thats what most have and the Hight Ph tests water in the alkaline specrum as it starts at 7.4 yes??

If your plants are looking light green... to me thats yellower than normal. Adding Iron will definitely not hurt your system if you follow that 1 spn to 1000L. Im putting in 18 spns at a time and the plants are looking great.

Do you have salt in your system? Dosing to 1ppm is good for fish health.

... just IMO

Cheers

Do what netab said re iron etc, it's worth it. I would chuck the tomms In too. Ph wint kill fish, unless it's really acidic or basic. A range if 6-8 is
Fine for fish

Yes, goldfish are pissweak. But cheap, that's why inthink alot if people use them to cycle systems.

Perhaps something other than ph is killing your fish??

I'm not sure, but atleast the minnows are doing well lol. I acctually added salt earlier today after it was dissovled in a cup. and only the lettuce leafs are light green, tomatoe, squash, cucumber, and collard leafs are all dark green. I think its normal for lettuce to have lighter leafs??? atleast thats what I see at the store. I also planted 1 of the 6 tomatoes just to see how it dose compared to the 5 still in pots.

Do the plants benifit from salt? I read that to much will get in the way of their photosynthesis, but i added half of the recommended amount which is 1tbsp per 5 gallons.

By the sound of it your plants are fine... if they start yellowing you know what to do...

Salt wont hurt plants... strawberries are usually the most sensitive but at 1ppm you wont see them suffer either I dont think... its usually up around 2ppm+ that you see them struggle... think thats right? Havent grown any yet so just going on what Ive read

How do you add iron? can I just throw in a rusty piece of metal? I know that may sound stupid but if it would work I'd rather use what I already have.

Salt will damage some plant at 2ppm. Make sure you use pure salt otherwise you'll harm or kill your fish. Any old table salt will not do.

Rust=iron oxide, not able to be used by plants but will take arsenic out of the system. Use chelated iron

Most people run their systems at 1ppm and will put the fish in an isolation tank if they need to treat them at a higher salt level... that way there is no risk of hurting your plants with too much salt. Its the anti-cakeing agents that are no good for AP... I think Bunnings pool salt for about $6 or $7 bucks is what a lot of people use. As freoboy said, just make sure its just salt with no additives.

Yup you need chelated iron - Yates is the most used brand... think its about $14 a box from Bunnings and heaps of other places.