Restarting a crashed reef tank


New member
My dad has a 26 gallon reef tank that crashed about 6 months ago due to a heater malfunction and has been neglected and just sitting ever since. Everything is dead at this point (I don't think there are even any pods still alive) and I want to help him get it back up and running, and I'm debating about the best way to go about it. Should the tank be completely drained and refilled? Would it be best to take the rock out and scrub them/rinse them off, then try to cycle it again with some live sand and/or live rock from my tank? (I have a 40 gallon reef tank that is going strong.) Or would it be best to just break it all down and start completely from scratch with new sand and everything? Any tips on how best to proceed would be appreciated. TIA

Sugar Magnolia

Mother of Dachshunds
Staff member
RC Mod
It depends on the condition of the rocks. Are they covered in hair algae? Was the tank topped off daily after the crash or left completely unattended? If it were me, I'd take all the rocks out and soak them in bleach water for a couple of days, then soak them in RODI water for a couple of days, then let them dry out completely. Toss the sand and start with clean, dry aragonite.


New member
I agree with the above statement. A friend of mine had a similar issue with his 80 gal tank.. He left it in bad shape after the crash for a few months and on the advice of a LFS he replaced like 90% of the water and let it cycle thru and could never get his levels to acceptable values to even add a clean up crew. He let it cycle for months running carbon and water changes but it turned out as a waste of time. He ended up replacing the rock and rinsing the sand and was back in service a month later.

I think it really matters on what his testing uncovers and what caused the crash. If its due to a contaminant I would def start over. My friends crash was a mystery so we are thinking a contaminant entered the tank.. And he was so disappointed he left the tank just stagnant for months. And went against my advice to start fresh and wasted time and money.. Your situation might be different but if it was me I would def start over to avoid any headaches


New member
Top it off, get water circulating. test parameters. it will cycle again. Water prob pretty nutrient poor. Make sure phosphorus is down before you start in on water changes. If not you might have an algae issue. Make sure all equipment is working right.See how it goes.


Empty tank into some 5 gal buckets, take rock out and shake it out in buckets. keep rock wet. fill tank new, put rock in. new sand or not.... fresh water. quick cycle and then its off to the races.


what them guys said.


Active member
Several years back while on vacation California had a rather interesting energy issue which lead to several outtages. One thing lead to another and the end result was me returning home to a crashed tank. This was my 100 gallon tank at the time which had various fish and corals.

I removed everything that was dead and which could be reasonably removed without more destruction. This was dead fish, snails, corals, etc. I then drained all water from the tank and sump, replaced broken powerheads and return pump, then filled back up with emergency tap water saltwater. Dechlorinated it, then let it do its thing. Basically kept a very short light cycle while I tried to figure out what to do next.

Not even 24 hours later the sandbed (which was rather deep @ 6 - 9" in various parts of the tank) showed life in it. I was pretty amazed. Rocks didn't show much. About a week later some zoa's that I didn't get cleared off all the way started to show some life. I did a water change about a week later and then put in a pair of clowns. I left it that way for about a year has I was pretty busy with other things and it was on auto pilot more or less.

Zoa's took over the whole tank. I later tore it down, moved the rocks and sandbed to two 29 gallons we set up, same with zoa's. The rock and zoa's seeded these tanks. The clowns I gave to a friend as they are too big for our tanks.

I guess what I'm saying is just clean up what you can or think is dead. Remove water, other things that are broke. Then treat it as a new tank. I think you may be surprised what lives. I know I was.


New member
It crashed due to a heater malfunctioning and heating the water up to how knows how much (off the thermometer), so it wasn't the result of contaminants at least. The pumps have been left on, so the water has been circulating, and he has kept the tank topped off. The lights have been off, so there's just a little bit of hair algae. All the coraline is dead and the rocks just have a lot of detritus on them, which is why I was considering removing and rinsing them. I'll go over and run complete tests on the tank this weekend to see what the current values are. Thanks for the feedback.