Just can't get the water buffered!

[Connie]

Hi! I'm Connie and I haven't posted in quite awhile. Our system is an IBC, 220 gal with 2 grow beds, 20 half grown tilapia (born in our tank). We have been up and running one year through a hard winter in NC. We moved to a green house last fall and we now have squash, tomatoes, lettuce, peppers growing quite well except the squash and some of the lettuce have developed brown edges. (Heavy feeding plants leading to K+ deficiency?) Here is the water problem.... We have good water parameters except the pH varies daily from about 6.4 to 6.8 or 7 and we have to add potassium and calcium carbonate daily, sometimes twice. If we miss, the ph drops below 6.4. The kH stays around 2 or 3 and I cannot get it any higher without raising the pH to 8 or 8.2. Then lowering the pH also lowers the kh right back down to 2. We have tried both city and well water as our source. The well water has kH of about 2-3 and the city water is usually 2. PH runs about 7.2 in both. Gh in both sources is pretty high. Our son is a water treatment operator in another state and has tested the pH and kh of the well water b/c he didn't believe what we were getting with our API test. He said we were right...Any help would be appreciated! 

[Jonathan Kadish NYC AA Chair]

It can be possible to add a longer lasting, slower acting buffer like shell grit so that the PH bottoms out at 6.4 or so. Then you can do your fine adjustments with a potassium buffer.

[Connie]

Thanks! Will try!

[Steve R]

You need aquabuffer. It is potassium bicarbonate and while it will temporarily raise your PH it will stabilize in a day or so back close to what you started at and raise your KH. http://www.theaquaponicstore.com/AquaBuffer-pH-Stabilizing-Kit-1lb-... That should stop your PH swings.

[Connie]

Steve R said:

You need aquabuffer. It is potassium bicarbonate and while it will temporarily raise your PH it will stabilize in a day or so back close to what you started at and raise your KH. http://www.theaquaponicstore.com/AquaBuffer-pH-Stabilizing-Kit-1lb-... That should stop your PH swings.

[Connie]

I see you posted this several days ago. I am just now getting back here. Thanks for your answer. We (husband and I) have been using the Ph raising kit for quite some time now. Is the stabliizing kit different? Will bicarbonate work better than carbonate? When we use the stabilizer, do we continue to use that or go back to the Ph raising kit?

I keep goldfish aquariums. Had many health problems until I learned about Kh and used Microblift's Kh Booster. I can keep the Kh up with that, but Ph stays up at 8 or 8.2 until the Kh drops. (Goldfish can do fine w/ that, but won't work for aquaponics plants or tilapia.) I have not ever been able to move Kh w/o moving Ph.   But you say the bicarb will raise Kh and the Ph will drop in a few days...? If that will work it will be worth it, even though we just got a new 5 lb raising kit!

Connie said:

Steve R said:

You need aquabuffer. It is potassium bicarbonate and while it will temporarily raise your PH it will stabilize in a day or so back close to what you started at and raise your KH. http://www.theaquaponicstore.com/AquaBuffer-pH-Stabilizing-Kit-1lb-... That should stop your PH swings.

[Keith Rowan]

measure your ph at the same time of day every day.. there will be a natural diurnal swing.... get some good readings before trying to chase your ph..

slow acting buffers work great, but as the name implies, they won't make any quick changes