Is there a chemist in the house?

[graveyardworm]

For about the last month I've been struggling with sps tissue recession and high nitrates. I think I may have found the problem, but not sure. About a month or so ago I emptied out a tank in my system and shut off the water to it. There's about 3 feet of pipe from the main to the valve. Today I decided to get the tank running again as a macro/refugium tank. So I turned the valve on and the stench of the water which came out nearly knocked me over. Hydrogen Sulfide? Could 3 feet of 1 inch pipe with stagnant water slowly leaching Hydrogen Sulfide into my water cause tissue recession and lead to high nitrates. I've got about 400g's of water all together in the system. The only corals which seem to be effected are sps. Nitrates are around 25-50ppm ( Salifert kit ). and even with large water changes never go down or stay down long. This is a recent problem, but the Nitrates did start to climb prior to the plumbing being left stagnant.

[Spuds725]

It's hard to know for sure but it probably didn't help....

I wouldn't blame just the stagnant water though-- you probably had alot of life (filter feeders) growing in the pipe that died when you turned the water off to it (probably got cold and/or starved)-- and whatver you got in the line is going to dilute throughout the system-- I don't know the specifics of what hydrogen sulfide would do.... it would certainly increase the nitrates

[bertoni]

Stagnant tank water will produce a lot of hydrogen sulfide, but there's no way for that gas to leach from pipe. I'd look elsewhere for the nitrate problem.

This article covers hydrogen sulfide:

http://reefkeeping.com/issues/2005-12/rhf/index.php

[graveyardworm]

The water in this pipe was open to water going into the system water. The water from the tee to the valve to tank was unmoving for about a month, but I hadnt really given it a secodn thought when I shut the valve off because it was still in contact with moving water.

[bertoni]

Hmm, one end was open to flow? Well, I'm still skeptical that the section of pipe would produce much nitrate, but it might be possible.

[graveyardworm]

I doubt it was the culprit as far as nitrates, and waht I think I got from the article was that the Hydrogen Sulfate eventually breaks down into Water and Sulfate, but I'm not sure how quickly this happens. Since I alleviated the problem my display has had 2 good days and the corals look a bit perkier, still though that could be because I've been doing large water changes and finally my Nitrates are under 10ppm.

[Percula9]

Do water changes more often to alleviate th nitrates. Add chaetomorpha to the refugium to help remove the nitrates.