[Steve]

I recenntly received a new 10.3 gallon pressure tank that I am using to store RO/DI water in. Last night I emptied some out and it really smells like rotten eggs. It is a pressure tank for RO water. My water that is just RO water (and not DI) does not have the smell. It is stored in a 10.3 gallon pressure tank also. Both pressure tanks were ordered from ReefPure. Also on another note. I ordered a replacement membrane from ReefPure where they claim their membranes to be just as good as Kent Marines. With Kent's membrane the TDS for the RO water was 9 and the RO/DI was 0. With ReePures the RO water is 24 and the RO/DI is 2.
Can the smelly water be used? I would appreciate some help on this because ReefPure is not real good at answering their emails.

[Rin]

Did you rinse out your pressure tank when you got it?

Are you using well water? If so, do you know if you have sulfur in the water?

The rotten egg smell comes from hydrogen sulfide. Most likely you have anaerobic bacteria growth in the RO/DI water that is causing the problem. The RO water is probably better oxygenated, which is why you don't notice a smell.

If the water doesn't look visibly foul, you can aerate it in an open container and get rid most of the hydrogen sulfide. It should be OK to use after that.

If you have a lot of sulfur in your water, it'll be a little more acidic than average--but probably still OK to use. Your sandbed will grow the bacteria you need to metabolize it. There are some who believe that this sulfur-fixing bateria is detrimental to the home aquaria. I don't know.

[Steve]

I am on well water, but I don't believe the water is unusually high in sulfer. Otherwise I would think that the RO pressure tank water would smell also. My only fear is that the RO/DI water is eating away at the inside of the pressure tank. The pressure tank is a RO pressure tank so I didn't think this would happen. I did not rinse out the tank before use. I have filled the pressure tank and emptied it out once right away after it was filled to do a water change. The water currently in the pressure tank has been in it for 4 days.