Freshwater to Salt conversion advice...Fish Only

[mrz2u]

So here comes a general question that will I am sure get lots of opinions stated as absolutes but here we go just the same…

Right now I have a 200 gal African tank that I have grown board with…well, somewhat anyway. I accidentally got a female yellow lab in there and now it is full of yellow labs at the moment and little else. The tank is over six years old in its present configuration. Many of the others fish that it began with have been lost over the normal cycle of things since I put them in there are mature males in the beginning.

It has two Eheim 2217 with a standard media pack and both return to the tank through a BioWheel Pro 60 each. There are also two Marineland Mag350 canisters that I just run with carbon.

What I would like to do is tear this one down and make a salt tank with some combination of if not all of the following…Lions (three or so?), a shark of some sort TBD later and perhaps a eel or two as well.

The question is what would you folks think of the filtration I have for a fish only tank? What else would you think I should have and must have.

I know what I would have to do down the road should I want to make any reef type changes, right now I am just really thinking of fish only cause I just don’t have the time or inclination to do the reef I would want to do.

[ErikH]

For a fish only with that large of a bioload..... You are going to be spending quite a bit on the front side.

Fish in a FO environment tend to be messy. Meaning pee and poop, lots of it. Within the top 2" of the surface water, alot of "fish byproduct" ends up in this zone. A calfo-style overflow extends 1/2 to 3/4 of the length of the tank which constantly turns that top 2" of water. In doing so that top 2" ends up most often, in your sump to be skimmed by an oversized, efficient skimmer. This will be a large chunk of change, unless you find something good used, here. A calfo would be two or three 1 1/2" or 2" holes drilled into the back panel of glass on your current aquarium. Then there is an acrylic overflow box for the water to overflow into. Some of our sponsors do this if you feel unsure about doing this yourself.

Run your drains into fine micron filter socks to polish the water and keep your sump free of debris.

Other than that, you need rock and sand. I would put at least 250lbs of rock in a refugium, as well as a Deep Sand Bed (DSB) and also run some chaeto (macro algae) to help export those nasty nutrients.

You may want to size down that list to maybe two lions and make that a snowflake eel :)

[ErikH]

Oh, and Welcome to MAAST.

[phippsj]

Could always move some of that rock to the display (FOWLR). Maybe a couple of really nice show pieces? Although I am not sure I would want to stick my hand in a tank with lionfish, sharks and eels to blow off the rock :)

[Aqua-Dome]

Saltwater tanks, especially fish only tanks, are hardly different than freshwater setups. For the fish you mentioned, your existing filtration is perfectly adequate. A wise choice would be to replace your gravel with an aragonite sand and add some live rock. Other than that, you only need to learn to mix your water to the proper salinity. Go slow and have fun.

[mrz2u]

...more

I have occasional ammonia in my tap water as is common in my area. I have had it with the crazy spikes on large water changes and this past weekend was a bad one…the spike was bad enough to take out about 10 fish! RO is on its way. This sucks cause were it not for this unpredictable ammonia and to a lesser degree the phosphates that are also there often, my water is perfect for Africans, Ph 8.0 and Kh of around 18-20…liquid rock basically. I never really considered saltwater cause I didn’t have RO and didn’t want to haul that much water from the LFS all the time but since I am about to get one going I have options opened up for me now.

I have a tank to make a sump with and a pump so I may get to that in the process but for now, lets assume we wont have that. I will just have to do more water changes till I get that squared away.

Corals and such may come at a much later date and for now it is very likely to just be fish. Planning on some combination of lions, puffers, triggers, large angels and larger tangs…none of which I believe will disturb the sand? I have ditched sharks and eels. I like the idea of clams too but I think there are some issues with triggers and puffers and clams? Also not sure if clams are diggers?

My tank is 24in deep so I have what I think is enough room to make 4 to 6 inches of sand and still leave plenty of swimming space. I don’t want to add a ton of live rock as I already have a rather extensive amount of the holy limestone that is popular in the AC tanks. I know it is not as porous as the live rock used in typical reef tanks but it is a little and I plan on the sand taking care of what the rock doesn’t.

I guess the question for now is should 4 to 6 inch suffice and what problems do you see with this planning so far, mostly the DSB?

I have heard that one reason for not doing the DSB in the main tank is the risk of say a power head falling and disturbing the bed which I plan to mitigate by placing sheets of lexan a little below the sand in areas where that could happen so that the depth of the bed in that area is not disturbed and or making sure that a sufficient amount of rock is on the sand in that area so as to also help prevent disturbance.

[ErikH]

You should buy the DI portion of the unit. You will need it for 0 TDS.

No clams with puffers or triggers. If it has teeth, or, lol a tooth, it will chomp down on corals clams and shrimp most often times. You will need a large skimmer to skim out all of the dooooooo.

don't worry about a powerhead falling. I have a good amount of sand in my tank and I have never had a problem with a powerhead falling and killing everything. Just alot of dust on corals and alot of slime.

Your rocks should touch the bottom glass, with that DSB in there, it could get unstable. A fish could dig a nice home underneath it and cause some wreckage.

Have you ever used copper in that tank? If so you will need to re-do the silicon. Copper will kill, well everything but fish, basically.

Don't overthink it, but you will need live rock.
You will need a skimmer, and a big one.
It would be easier for you to start with small fish until you get the proper setup finished before you just kill alot of fish. You need to be able to export nutrients, no fuge, no skimmer, no LR, and only sand + heavy bioload = disaster waiting to happen.

You can't circumvent nature that much :)