Raising pH
 

Forgive me for asking this question which I'm sure has been asked, but I was not able to find an old post that answered this

Does anyone know what can be used to raise pH? I know baking soda can do it, but the sodium worries me. I've tested my RO water with a pH meter (3 point calibration) and found that it hovers around 5.1, which is on the low end. I'm still trying to get some MSU for RO water, but until I can, I'll have to resort to the current fertilizer which makes my water slightly too acidic.

Ideally, I'm looking for anything that can be commonly found, but specialty horticultural pH booster recommendations are also welcome.

In a potting mix, often bone meal or oyster shell is used to increase PH. Oyster shell is very cheap and is sold in 50 lb bags in farm supply stores for about $10. It is used to aid in egg production by chickens.

I wouldn't worry about using baking soda if it's only a short term fix, it shouldn't do much damage.. i know people that use sodium hydroxide (drain cleaner)! I think Potassium silicate is a good horticultural one, and i think also lime (?). But getting pH up is not a problem i have, my water is fairly hard. Maybe you could use some of your town water?

Calvin - An easy thing to get is ProTekt from the makers of Dynagrow. It's a potassium silicate solution that I've used to raise my fertilzer/RO water pH. You have to experiment to get the drops per gallon ratio (I aim for 6.4). The hydroponics store near me sells a pH up solution that is potassium hydroxide - works just as well.