Multiple waters changes a week?

I have a 12 galling long with lots of branches coming out the top so a lid is not an option nor am I interested in trying to get one custom fit. I understand water evaporation is to be expected. My question is,would it be OK to top off 2 to 3 times a week? Does this cause any imbalance in my tank? I do weekly 25-30% water changes. My tanks are fairly new and the weather is heating up so I'm sure this makes a dramatic difference in evaporation for the summer months. But I just love me a full rimless tank!
I meant to sat in the title multiple TOP OFFS a week

 

It should be fine. I run a topless tank and I lose about an inch a week and i top it off regularly. Shouldn’t mess with anything.

 

Topping off is fine, should not cause any imbalance unless your water used for topping off is high in anything like phosphates, etc. If your water is good, topping off will help prevent imbalances from evaporation.

 

You may not have an issue but minerals and dissolved solids don't evaporate so they will build up if topping off with any water that has them. That's why I like to only top off with distilled water... it is most like the water that actually evaporated. I would do this especially on tanks with high evaporation rates.

 

You may not have an issue but minerals and dissolved solids don't evaporate so they will build up if topping off with any water that has them. That's why I like to only top off with distilled water... it is most like the water that actually evaporated. I would do this especially on tanks with high evaporation rates.

If I had store bought distilled water sitting at room temp is that ok to use? And should I add prime?

 

If I had store bought distilled water sitting at room temp is that ok to use? And should I add prime?

Yes, room temp distilled water is perfectly fine. No need to condition with prime because it doesn't contain chlorine or chloramine.

 

I leave some tap water sitting in pitchers for top offs. As long as you continue doing your regular water changes you will have no problems. The tap water degasses in 24hrs and it cheaper than buying water.