Stubborn to cycle tank

animateash · Jan 20, 2020

Been trying to cycle the tank for my dwarf seahorses for about a month now. It had been running well for 6 months and then a big nitrate spike threw everything out of whack even after a 100% water change. Seahorses are now in a hospital tank with their sponge filter and are safe, but i have been unable to get the bio filter in their display tank back on track. I've tried ammonia dosing. I've tried adding filter media from a friend's tank. I've tried Seachem Stability, Dr. Tim's, and Microbacter 7. Nothing is sticking/populating! Best I've had was the beginning of ammonia processing with the ammonia dosing method, but then after 2 days of what seemed like progress it would stall out and cease entirely.
Currently trying a cycle with fish with 2 mollies (salt water acclimated), but they've been at 2.0ppm for 4 days now...no progress despite adding a full bottle of Dr. Timm's and some Stability.
I've been reading a lot about cycling online and I can't figure out why I have yet to make any head way.
Any idea why I can't get going? Only products I haven't tried yet are instant Ocean Bio Spira and Microbe Lift, but aren't these just the same things I've been using?

4gallon tank (I know..very small, but appropriate size for dwarf seahorses)
Aqueon HOB filter that is running well
Filter media is some coarse grain black sponge and ceramic filter media (Fluval, etc)
Dwarf seahorses should be kept with a bare bottom tank, so there is no live sand, gravel, or live rock in the equation.
Current pH 8.0
Have been testing with the API kit

Any thoughts appreciated. The seahorses are really sick of living on the bathroom counter...

reef lover · Feb 2, 2020

I would suspect without the presence of porous surface to grow...the bacteria cant populate. Can u put a couple small pieces of dry pest free rock for it to grow in?

animateash · Feb 2, 2020

reef lover said:
I would suspect without the presence of porous surface to grow...the bacteria cant populate. Can u put a couple small pieces of dry pest free rock for it to grow in?

I do have one such piece in there, probably been in for 3wks or so. This entire time I have had biomedia in the filter and shouldn't that be serving the same purpose? I'm finally getting my nitrites cleared just yesterday but this took way longer than I thought!

reef lover · Feb 2, 2020

Sometimes our medias are more nitrate factorys then anything especially if theyre not cleaned often which one might do if trying to salvage thier bacterias upon them.

animateash · Feb 2, 2020

reef lover said:
Sometimes our medias are more nitrate factorys then anything especially if theyre not cleaned often which one might do if trying to salvage thier bacterias upon them.

Understood. I think that's what happened when the filter maxed out in the first place. Chucked the carbon altogether to support more media for bacterial growth. I do also have a seasoned sponge filter which will be transferred back into this tank when ready for use.