sponge filters for salt water???

[Magnum Man]

the seahorse thread got me thinking about my attemp to keep them back before the internet…

I looked, and the AI suggestion for a filter, was a smaller hob filter, and a protein skimmer, as the sea horses don’t do well with much current… I may have tried a sponge filter back in the day, and it is not suggested today…

my question is, do sponge filters function the same in salt water as they do in freshwater???

 

[Back in the fold]

No , they do not . There is no bacteria in salt water .

 

[Magnum Man]

well there is bacteria, but assume no beneficial ( nitrifying ) bacteria…

 

[Back in the fold]

well there is bacteria, but assume no beneficial bacteria…

I should have attached a disclaimer on my previous post . “ I have absolutely no experience with marine aquariums and anything I say can be ignored “ .

 

[gwand]

Salt water aquariums need to be cycled too. They need a different set of denitrifying bacteria compared to freshwater tanks. The bacteria live in the porous rocks more so than any filter.

 

[Magnum Man]

if they colonize the porous rocks, one would think they would be drawn into a sponge filter???

 

[GaryE]

I went looking even though I never have had and never will have a saltwater tank. It seems they work, but are viewed as short term fixes, maybe for QT. There's also the question of how they add to salt creep via their bubbling, a not insignificant problem.

 

[raylove]

Back in the day when I kept marines filtration was invariably via undergravel filters with powerheads. Biological filtration is definitely a thing in salt water and I always assumed canister or sponge filters would work but generally these were considered not to have enough surface area compared to a deep gravel bed.
I think I've said somewhere before that I once left my powerheads off for a day accidentally and I was terrified that I might poison everything if I simply turned them back on. I therefore removed all livestock and put them in a bucket before restarting. Once I did, the water stank to high heaven and ammonia was off the charts. I went to bed not knowing what I was going to do the next day, but next morning, to my surprise, the smell had gone and all tests were good. I returned all livestock and they were none worse for their overnight stay in a bucket!
This seems to confirm that marine nitrifying bacteria are highly efficient once established.

 

[Back in the fold]

Salt water aquariums need to be cycled too. They need a different set of denitrifying bacteria compared to freshwater tanks. The bacteria live in the porous rocks more so than any filter.

You’re thinking of what is known as “ live rock “ . I don’t know exactly what it is that’s live or anything but it’s more than bacteria . Some marine aficionado may know .

 

[Magnum Man]

when I bought live rock for my reef tanks, they were not claimed to be full of nitrifying bacteria, they were full of feather dusters, tube worms, and all the micro critters on the rocks

 

[GaryE]

I feel like we're blind and trying to draw cathedrals. Where are the saltwater people when you need them!!!???

One of the many things that have kept me as a freshwater keeper who has always avoided salt is the technology - you can easily run ultra-simplified set ups if you wish, with sponge filters and homemade gear. The local auto shop chain used to sell carwash sponge that cut in two, with a little drilled pvc became ideal sponge filters, and I used them for years. I still use spitting filters - made from large juice bottles cut up with holes drilled in them, a little wider tubing and media. Hide them behind decor and they do wonders. Meanwhile, my saltwater friends have much more complex devices doing about the same thing. Saltwater has always struck me as more of an engineer's pastime.

 

[Magnum Man]

I got out of salt 30-40 years ago, and at that time sump systems were the “high tech” but I also ran under gravel filters back then, algae was a problem blinding over corals, or live rock, water changes were still needed, but all the water was gravel vacuumed out, this was way before RO water, so my salt water was mixed using salt and my well water, which likely also had nitrates in the water back then, which would explain the high algae growth… my reef tank used a combination of high pressure sodium ( for sun rise / sun set light ) and metal halide for mid day lighting

 

[Back in the fold]

@Magnum Man Yes ! That’s what I was thinking about live rock . I saw some in a local shop once and it looked like creatures on it .
@GaryE Yes , where are the saltwater people ?