I built myself an acid injection system for MA, but think I may be loosing the strength of the MA as it sits in the storage tank waiting to be injected into the pool.
I dilute my MA 50-50 with water and store it in a 5 gallon container that has a 1/8" barbed fitting that is used as an air vent. I can't let the pump create a vacuum in the tank or it wont work as the pick up tube would collapse on itself.
I don't have specific numbers to compare, but it appears that the acid solution is not working as well over time as pouring the full strength acid directly into the pool. Previously I thought I was using about 1 gallon of acid per month, so I setup my pump to inject this amount into the pool and it does this quite well. I have noticed that I still have to add about 1 gallon of acid per month in addition to what the pump is delivering.
This could be that I was not correct in my assumption previously because I never logged my acid usage. I just put it in and periodically reduced TA after adding fill water. But I was wondering, could I be loosing MA do to evaporation or some other means?
How do the "commercial" tanks handle the venting of the tank so that they do not form a vacuum?