Daily Water Changes

[rocketlily]

I am currently reading the book, Marine Reef Aquarium Handbook, by Dr. Robert J. Goldstein, and he recommends a daily water change of 1 percent for a tank 100 gal (1 gal) or for a tank half the size, change a gallon every other day.

My question is, that for a 20 gal nano tank, when you should be changing 2-3gal per week, would it be better for the tank (in a perfect world) if I changed a litre per day. This also brings me to my second question. I am using Red Sea Coral Pro salt for RO water. How big of a batch of water can I mix and how long can it sit before using. Can I mix 3 gals. in a pail, cover it and use it all week for daily changes?

[michika]

Most people actually change weekly, bi-weekly, or monthly. However if you want to go the daily route Red Sea will last for about a week provided you have it running with a pump to keep it mixed and a lid to prevent evaporation. You will probably want to test it before you use it though. The biggest I've ever mixed, and it was with Red Sea Coral Pro, was probably 55l (in a garbage can), and it ran for about a week or so.

[Matt]

Why wouldn't it last (theoretically) indefinitely? Either bottled and capped or mixing and heated?

[michika]

If it was airtight I'm sure it would be fine. However when there is a bit of air exchange it seems to put an expiration on it. If you don't have enough flow to keep it mixed to get what I call Skank Water....its nasty.

[christyf5]

Why wouldn't it last (theoretically) indefinitely? Either bottled and capped or mixing and heated?

Unless its completely sterile it will develop a bacterial biofilm in it on the containers surface and those bacteria may produce unwanted bioproducts (ie. your RODI water isn't as pure as it once was).

[hummer]

Unless its completely sterile it will develop a bacterial biofilm in it on the containers surface and those bacteria may produce unwanted bioproducts (ie. your RODI water isn't as pure as it once was).

What if you fill up one of those garbage bins with RO water only? Would that be sterile enough sitting for a week or so? Then he can add salt in a seperate mixing container a day before he wants to do a water change.

[christyf5]

I would imagine it wouldn't be a problem letting the water sit for a week, lots of people do it. I wouldn't let the water sit stagnant though. I'm not sure what the bacterial growth rate is for a week. I usually make up water the day before I need it. I have found that if I let water sit in the container for too long (especially repeatedly, say make up water let it sit, then refill the containter immediately) I can wipe out a goodly amount of brown stuff off of the side of the container after I empty it.

[erikages]

I mix 25 gallon batches of salt H20 whenever I do a water change. I use rodi water, then throw a maxijet in the bottom of the "garbage can" (which is actually a white, food-safe container with handles and lid from a wine making store).

I've leave the water stirring for a day or two before putting it in the tank in two batches (one day after the other).

I wouldn't leave 'fresh' salt water to sit for more than a week -- at the most. Speaking just personally, what's the point of ro/di water if we let it degrade before using it?

Erik

NB: for my water topoff water (also rodi in a 5gallon foodsafe bucket) I leave an air bubbler in the base of it to provide some water circulation. This water lasts about a week as well.

[Drock169]

The only thing I think I have to add, is that if I leave water sitting around for awhile I also like to add an airstone in addition to the pump

[Brent F]

My question is, that for a 20 gal nano tank, when you should be changing 2-3gal per week, would it be better for the tank (in a perfect world) if I changed a litre per day. This also brings me to my second question. I am using Red Sea Coral Pro salt for RO water. How big of a batch of water can I mix and how long can it sit before using. Can I mix 3 gals. in a pail, cover it and use it all week for daily changes?

Small frequent changes are better for maintaining a constant water quality. But, if the changes get too small of a volume it gets difficult to suck up the crap with the water - you might not be able to vacuum up the debris in you tank if only siphoning out a litre at a time.
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