Backyard Aquaponics
A place to discuss aquaponics

Hello everyone!! I've also posted this in the new member introduction section but I feel that wasn't the proper place. I joined today after 2 weeks of fishless cycling. I'm having a high ph issue.


My system consists of a 300 gallon stock tank (2) 6' by 4' grow beds each with a bell siphon and gravel with a continuous running pump. I started fishless cycling exactly 2 weeks ago today. I planted my plants the first day added my ammonia everyday until I was consistantly between 1 and 2ppm and on the 3rd day I put a quart of maxi crop liquid seaweed in the water. The plants look great and are already showing much new growth. The nitrites are consistantly around .5 to 1 and just 2 days ago my nitrates were around 20ppm. My problem is my ph is at 8.2 and for the first week I didn't know why. I tested the gravel with vinegar and no fizzing occurred. The source of the gravel assured me there was no limestone mixed in with what I bought. After the first week I rememebered that when I purchased my house the well water was tested as being acidic, so we purchased a neutralizer as well as a softener because it was hard as well. I always thought the neutralizer brought the water more toward neutral but instead it comes out of the tap at 8.2. I believe the media used is calcite. So I believe that is 100% my problem. I waited two weeks thinking the nitrification process would gradually bring the ph down but there has been zero change. What can I do? With more patience will it come down, or is a massive water change needed or is there a product that can remove/counter the calcite? As I said the plants are doing well, but would probably do better with a correct ph. I'm just more concerned about adding the fish until it's fixed.

I'm in a similar boat with my system. Everyone has said the let it work but I am using scoria and not calcite. I don't know how that impacts it.

My system was around your range for 6 months. Everything (apart from the dwc) seemed to grow alright, fish seemed fine. Recently I've been treating my top up water with hydrochloric acid, and it's slowly coming down.

But the nitrification process will bring it down, depending on a variety of factors like carbonates in your water, tap water ph range, fish load and a few others.

You're two weeks in, I wouldn't sweat it.

Here is my tip for getting the pH down and your system is less than 18 months old and your grow bed media has been confirmed as being neutral.

If you drink.

1. test pH
2. if pH OK go to step 7
3. have a drink
4. have you repeated step 3 three times or more (if on American beer say five)? If yes go to step 6
5. go to step 1
6. you are too drunk to accurately test the pH. Go to step 7
7. Test again in one week.

If you don't drink

1. test pH
2. if pH OK go to step 7
3. have a drink of your choice
4. do you need to urinate? If yes you are possibly unwell due to over hydration (or if with a caffeinated drink dehydrated), go to step 6
5. go to step 1
6. you need to go to the toilet too often to accurately measure the pH
7. Test again in one week.


Seriously, give it 18 months and you will be screaming about raising your pH due to the chemical reactions in the grow beds. Enjoy it while you can.

I waited two years for the pH to come down (also used scoria) and it eventually did. Giving it time is probably the best option but if you feel confident and know what your doing when working with acids then the instructions for using Hydrochloric Acid to adjust the pH are in this thread - http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=20156&start=45

He is doing his by adjusting the top up water (already has fish in the system)

The amount of acid used is different for every system. If you look around later in the thread IAP mentions how much he started with (might give you a starting point if you decide to try this).

Thank you for the responses everyone. I plan on just being patient and things will work themselves out.



Funny stuff Jeff I have already been following your plan even before you suggested it. When I'm ready to add the tilapia will they mind the 8.2ph if it hasn't dropped by then?

Just ease them into it. Put some of your tank water into the bag with the fish, and let them get used to it for 30 minutes. Don't drop them all in there.

However, tilapia owners might know better than me. We can't get them here.

It took less than a month before my pH was plunging below 7.0. Go to step 4 in Jeff's guidelines for non-drinkers, locate yourself near a GB, check that no one is watching, and have a slash ... the magic ingredient is pee

My ph is still above 8 and I am well over 2 years with it running.

That is a lot of drinking. Any problems with plant growth or fish health at those levels?