Some problems after moving FOWLR


New member
Hi everyone. I'm looking for some feedback on some issues I've having after moving my tank FOWLR back in the fall.

So, I had a pretty minimalist sumpless (i know, i know) FOWLR up and running for a few years without any major issues. 55g, HOB Aqueon filter, HOB Tunze skimmer, Current USA LEDs, a couple powerheads. Kept bioload pretty light - couple clowns, a couple damsels and a flame angel. 5-10g water change and changed out 1 or the 2 filter cartridges every week or two and things were stayed mostly clean and clear for years. Little bits of GHA here and there but nothing I couldn't siphon out. One strange variable with my set up: instead of sand, had a custom cutting board bottom. Had issues with critters growing in sand years ago and switched it out to cutting board. Worked fine -- even got covered in some pretty coralline algae.

I ran into some problems when the family moved late summer. Due to renovations I couldn't put the tank right back together after the move. So I moved the fish and some rock into a temporary 15g tank for about two weeks. They were surprisingly fine in there. The rest of the water and the rock I kept in buckets with powerbeads to keep everything alive.

Once renovations were complete, I set the new tank up just as it was in the previous house - only change was a new HOB filter. Within weeks I had a fish die off and algae problems like I never had before. All my levels have stayed low throughout so I don't think I've had a tank crash or new cycle. But I now have GHA all over the place, harder fibrous green algae growing off my rock. Haven't been able to stay ahead of it with basic water changes.

Trying to figure out what's different this time around and what I can do to get back in the right direction...

Here's what I've tried...
- dose with vibrant - knocked out some GHA the first time, but not much effect on subsequent doses
- ran GFO in an old phosban reactor I had - no effect
- lights out - no effect
- minimized lighting schedule - no effect
- added chemipure and purigen to HOB filter
- LFS guy recommended an tuxedo urchin and about 10 snails - they've done a nice job of clearing out maybe 30% of algae but still seems like its growing back faster than they are cleaning

Not sure what to try next... other than a 80% water change or something like that.

One question: should I even have filter pads in the HOB filter? They get messy and clogged so fast - I'm wondering if maybe that's where the nitrates and phosphates end up coming from. Might be better just getting rid of the pads and letting the purigen and chemipure flow? Most of the mechanical filtration happens from my siphoning anyway.

Any feedback would be greatly appreciated! Very frustrating that I had a decent tank for years and now it's a mess.


Premium Member
Your balance got thrown off. You probably had a good population of denitrifying bacteria in your live rock that took a hit and it will take a while to come back. The algae was waiting in the wings and is now the one keeping your levels low. You could definitely add another rash of snails. If you can find a money cowrie I find they really will chew through algae and as a bonus they love cyano if you ever have any. They're totally nocturnal so you will almost never see them though. Also you might want to avoid anymore Vibrant. Not sure if you saw the testing done over on R2R but it looks like it's just the same algecide as Algaefix and not bacteria at all. Having said that, dosing some Brightwell Microbacter 7 and Dr Tim's one and only are good options to increase your good bacteria populations.