topping off

Hey there-
I have a saltwater tank (56 gal). I need to top off due to evaporation. I realize ro/di freshwater is the way to go, but I do not have a setup yet for that. Is distilled water from a store OK? My salinitity is getting high so I want to bring it down slowly. I was figuring maybe a half gal a day would bring it down slow enough or can I go more? Right now it is about 1.029.

 

Grrrrr.. I have never used that.. I have used though is Walmart does sell 1 gal water that is RO water. I believe it will have a green cap. On the label, it will state processed by reverse osmosis. Yeah, 1.029 is a little high. I keep mine at 1.025

Get a RO/DI system. It is well worth the money!!

 

If a RO/DI system is not in your future distilled water is you next best choice. Bottled RO if it is intended for drinking water often is remineralized so it tastes good so will raise the TDS. Prepackaged RO/DI is rarely found in a store but may be found at a LFS in bulk, often you buy a 5 to 7 gallon jug and they refill it for like 25 to 50 cents a gallon. My only reservation here is you are at the mercy of the LFS as to whether they service the RO/DI properly and without a TDS meter you have no idea of its quality.

Vending machines are usually RO only and again for drinking water so may not be all that pure. I always recommend someone buy a handheld TDS meter and use it before purchasing water from any source.

 

Personally, I'd steer clear of distilled water, unless you know for certain that the distillery doesn't use copper tubing. Copper breaks down and taints the water, and while the level may be safe for drinking, in time it will build high enough to wipe out your bio filtration, as well as corals and inverts, as copper does not evaporate or dissipate from your tank. Also, the only distilled water I can find has been remineralized, which will create the issues pointed out by AZDesertRat. You'd need to read the fine print there, as well.

I agree with ComputerJohn-- an RO/DI system should be your next investment.

 

Copper has not been used in most commercial distillation units for years and years. Most are glass or epoxy lined exotic metals like titanium so copper is not an issue.
Most prepackaged distilled water will be fine. Its not the same as owning your own RO/DI but it will get you by if you don't need muc hwater for a small system. If you are using very much though a RO/DI is the way to go, I have done many calculations and it works out to less than a nickle a gallon making your woen and that includes the water and sewer rates as well as the replacement filters and resin. Doesn't take long to pay for itself.

 

Truthfully, I've not visited (or studied) modern distilleries. I've only noted that it's still a concern on SW aquarium websites and forums.

Don't know how much water he loses with the 56g, but I have to add 1-1/2 to 2 quarts daily to my 29H. To me, that's enough to warrant using RO/DI only. Also, you'd still need to ensure that the distilled water hasn't been 'enhanced' with vitamins/minerals.

The whole point for my first post. Don't take my wrongly, I'm not saying you are incorrect; but when giving advice, I prefer to err on the side of safety.

Cheers

 

Ive used distilled water from walmart in a pinch to no ill effects

 

Distilled water does not have additives, it is simply distilled and bottled. RO drinking water often is remineralized so it tastes good but not distilled which is used for things like car batteries, steam irons, humidifiers, lab testing and the likes.

 

I'll concede that I haven't actually shopped for distilled water, and I'm sure you're right for the most part, as that would make the most sense; However, a local convenience store sells only one brand, which does have additives, found in the drinking water section. So I was only advising that one double-checks.

 

I would love to know that brand, I have never ever seen remineralized distilled water in 35 years in the business. If you get by there grab the info off the label if you would please.