Probably not the right forum for this question, perhaps an admin will move it (getting started?).
However, what are you using to test your water?
Strips are netoriously inaccurate and may be the reason for that low reading. Holwever, if those numbers are correct, you can
use baking soda to raise your pH some. However, you will max out around 7.8 and you will need something to raise it beyond that. A pH buffer will work and it has a very similar make up to baking soda, but a few different ingredients to get the higher pH. Most Alk
buffers (which BTW is what baking soda realy act as) will raise your pH to the target of 8.4 while also raising alk
, which in the end provides better pH stability.
Glass covered tanks trap CO2
in the water which reduces pH, having better air flow helps this problem.