Rotten egg smell upon startup after repairs

[skeeter_ca]

My sump starting leaking at the seams. It took me a couple of days to repair it and put it back online. Everything was fine. After a couple weeks it started to leak again. I took it down and just ran the tank sumpless with powerheads. It seemed to be working ok without any problems for a couple weeks while I got a new sump and set it up. Added new water into the tank slowly to acclimate the fish to the new water and it slowly spilled over down to the new sump. After sump was full(about 30gals) I switched on the pump. After a couple minutes I noticed a familiar rotten egg smell. Oh, crap, I said to myself. Hydrogen-Sulfide. There was nothing I could do. I ran the pump and aired out the House. Everything had been drained so I thought. I now believe my chiller had not drained and may have had about a quart of old seawater setting in there for the weeks while waiting to install the new sump. I run skimmerless so carbon is about only thing I could do at the moment. The next morning I had lost two fish and maybe two shrimp( I hardly ever see them). I am going to do 5 gallon water changes everyday now for about a week.

Is there anything else you recommend doing?

 

[Minkota]

I had same thing one time and it turned out to be an exploded heater.

 

[skeeter_ca]

Heaters still good. Using a ranco to control them.

 

[d2mini]

It's normal.
Stagnant water goes south really quick.
Carbon and water changes are about all you can do.

My system got shut down earlier this week so this weekend i've been dismantling plumbing, pumps, etc. Whooooodoggy. Thats some stinky eggs. lol