Maintaining a stable PH in a static water reservoir

[golfnrl]

I'm looking for a way to maintain a stable PH in a static 13 gallon water reservoir. I have put together an auto watering system for my plants as I have to be away for about 10 days. My three girls are growing in soil. I've been experimenting and have noticed that after I have adjusted the PH in my reservoir to an acceptable range it begins to rise, and after a couple of days it is as if I never adjusted the water. The PH of the tap water I'm using is about 7.5 out of the faucet. I adjust mine with PH Down after adding molasses and nutes to about a 6.3. I'm wanting to try and have the water in my reservoir maintain that 6.3 range while I'm away.

[Tersky]

First off, not sure if you want to use molasses in an autofeed system. For 10 days it might be ok but having organics in piping breeds bacteria, good and bad.

Second, are you using an air stone for the res? If so, dont leave the pump on full blast. Ph rises with water agitation so the more air pushed into the water the faster the ph is going to rise. Ph rise is normal and natural which is why hydro growers are constantly checking res and adjusting.

Third, i know of no way to maintain ph of a res for 10 days without fluctuation and without adjustment. I check my res twice a day, granted i use 2gal buckets. There are products that supposedly can do this (https://hydrobuilder.com/zelda-horti...Q0IjoiOTEwMyJ9) but i have never used them and am a little skeptical plus they are more designed for hydro than watering soil.

[golfnrl]

Tersky Thx. I hadn't considered the bacteria aspect with the molasses. That tilts things over to not using it. I am using an air stone. I'll adjust the pump and see if that slows the PH rise. I'll check out the link.

[Toker1]

Ph will rise and fall with temperature. Also new plastics will effect PH for the first few weeks of use.
You can try adding PH buffers to the mixture to stabilize PH in a reservoir. Or go the high tech route and get a dosing pump to adjust it with a PH sensor switch. How much do you want to spend on stabilizing PH here?
yeah, molasses in drip feeders will clog up the lines over time. If you feed them heavy before you leave, you can just water them for the 10 days you are gone. Then feed them again when you get back. They will be all good.