Top off amount

[Bruce7267ad]

so I live in Arizona where it gets really hot although I keep my house at 78 I still get a lot of evaporation out of the top of the sump otherwise the main display tank is covered and I was curious how much freshwater can you put into your tank a day without ticking off your corals cuz if I even dump a gallon or half a gallon in I noticed they all close up

 

[andrewey]

There isn't a limit to the amount of water you can put in to replete the evaporated water- the limit is based on the salinity change (and/or possibly the pH/temperature change depending on the water) after topping up. This is what is harming the coral. Therefore, you should spread your top off over several doses- this can be done manually or you can make/buy an automatic top off to spread the doses out.

 

[themcnertney]

Requires a bit more info to answer. However, you should have a water line that should remain constant elevation. Best way of doing this is with an auto top off tank. A float switch will automatically send fresh water into your sump and remain a consistent level and no worries ever of having to figure out how much water to add.

 

[Bruce7267ad]

Would you guys say don't add more then half a gallon per day I don't have and auto top off unit and I'm on a budget so I manually add water back in

 

[Fishbird]

As others have said, how much you add depends on how much evaporates. You need to top off because water evaporates but it leaves salt behind so the more evaporation you have (without topping off) the more your salinity will rise. Measure your salinity in the tank. When it is where you want to keep it, put a mark on your tank using a sharpie to show where the water should be. Going forward, whenever your water dips below this line, add fresh water to top off. That way your salinity should stay constant.

If you're finding that your corals are annoyed by the swings you're experiencing I would try and get in the habit of topping off when you first get up, before you leave for the day (if you leave), right when you come home, and when you go to bed. Make the swings smaller. Maybe also experiment with putting something solid over part of the tank at night to lower evaporation rates?

 

[beaslbob]

as long as you use ro/di water there should be not problem replacing the small amount of water the evaporates. 5-10% should be fine. It you wait until 50% has evaporated then that can be a problem. But daily tops not so.

Plus the ro/di is only for sensitive corals. For fo for fowlr tanks no problem.

my .02

 

[Albertan22]

I go

Would you guys say don't add more then half a gallon per day I don't have and auto top off unit and I'm on a budget so I manually add water back in

I go through a little more than 2 gallons per day on my 180 gallon tank. I use an ATO though so the coral doesn’t notice it.

 

[Coastie Reefer]

Get an ATO it will make your life easier... There's not a set amount of freshwater that is detrimental, it's all based on the amount of evaporation you have. Considering you live in AZ, I'd assume that's a very dry climate and it is causing more evaporation. How often are you topping off... if you're topping off everyday it shouldn't be an issue, but if you are topping off once a week your salinity is likely swinging a decent amount and your corals are likely to not like that.

 

[X-37B]

My 120 evaporates 2 gal a day. No way am I running a tank without a dedicated ato, fish only or reef.
You could setup a gravity fed ato. It works just like the office 5 gallon water unit.
When the level is reached it adds water and stops when the water level goes up. Pretty simple to install.

 

[andrewey]

@Bruce7267ad- I think you're missing my point with asking for a set amount. For example, half a gallon at once won't matter in a 400 gallon tank, but would certainly cause some issues in a 5 gallon nano . We simply have no way of knowing how much is too much as you haven't provided the volume of your tank...

Additionally, we also don't know the water temperature of your top off. If it's coming from your cold water tap through your RODI and coming out at 50, that will make a bigger difference then room temperature RODI.

Ultimately, if you're manually adding water, you should be testing with a thermometer and refractometer to ensure they're not impacted too much by your additions. If they are, reduce the volume of each addition at one time.