Freshwater 20G To Marine

[TropicalNorth]

I've got a 20G freshwater tank set-up as a breeder tank at the moment. I was just wondering what I would need to do to convert it into a saltwater nano tank. I'm fairly experienced with freshwater but I only know a bit about saltwater.

What the tank has now:
800l/hr (205g/hr) internal sponge filter
55w good quality heater
Hydrometer and Thermometer

What I think the tank would need:
A skimmer (size?)
Salt + Buffer (my water is acidic) Do most salts come with a buffer?
Live rock (prefer to only have a small amount due to weight)
Lighting (Is this essential for a tank without corals etc, the tank currently gets indirect sunlight and a small amount of algae is present. Would a single fluorescent be enough.)

Inhabitants I would like:
1 Clownfish (not sure what species, my LFS has Ocellaris Clownfish, Tomato Clownfish and I think Black and White Percula Clownfish)
A goby (I know of a few species, open to suggestions, must be commonly found)
A few invertebrates (shrimp, snails)

The main constrictions are money (hence the not wanting fancy lighting) and weight. If you think this would be a bad idea (skimping) please say so. Thanks.

[rbell219]

In my experience (a painful one) bigger is better in saltwater for beginners. Small problems escalate quickly to very large problems in small systems. Seriously consider going to a 55 or bigger<--trust me, you will save yourself time and money in the long run. You'll need to do weekly or bi-weekly water changes and constantly monitor the water quality.
Skimmer<--like I said above, in a small system you'll be doing at least weekly water changes so skimming isn't exactly necessary. There are many nano skimmers out there or you could get a hang on the back model. You can't over skim in my opinion so I'd get the smallest big tank skimmer you can afford.
Salt will help buffer your water, but you may need a buffer--no way to tell until it's running.
You want at least 1lb live rock per gallon no matter what size tank for good biological filtration. Especially with no sump.
Lighting--any light will do for fish only, but 2 watts per gallon would be as low as I would go.
Goby---depends on the type. Some need a constant supply of copepods usually generated by a refugium. Let us know the specific type and we can help better.
Ocellaris clowns would be better in a small tank. They are schooling fish though so do 2 and get em small.
Cleanup crew quantity depends on the type. Each snail and crab and shrimp has a reommended "per gallon" amount.

So in summary---get a big tank. lol

[mooman]

I've been running nano tanks of 20g and under for over a year now and have never had any of the "crashs" that people are always warning about. I know it can happen, but with proper diligence it shouldn't. All you really need in smaller tanks is liverock, water movement (powerheads), and heat. No skimming neccessary. 25% water change weekly (don't skip a week) using ro/di water is a must for reefs, but I hear is not as important in a low light FOWLR tank (I've only kept reefs).

A nice stocking plan for a 20g would be a pair of ocelaris clowns and a bottom dwelling "shrimp" goby (watchman goby, highfin banded goby......).


You can't over skim in my opinion so I'd get the smallest big tank skimmer you can afford.

I don't think that's true. I keep mostly soft corals, and they look great in my unskimmed water. Other friends that have huge skimmers have terrible luck with softies but their hard corals look great. Different corals prefer different water conditions. Remember a skimmer does not distiguish, it removes everything. There is a growing movement in nono reefing that does not believe skimming is as important as the rest of the hobby makes it out to be.

[rbell219]

With proper diligence are the key words there. A lot of people automatically think a smaller saltwater tank will be easier and cheaper. Generally it is exactly the opposite. And I did say that a skimmer wouldn't be necessary. They do remove more than waste---iodide, fatty acids, carbs---but they tend to do more good than harm.

[Squawkbert]

my $0.02 - Alternative: FO w/ sand, UGF.

A home made UGF (1" PVC rack & lift tubes, drilled & plastic screen covered) w/ power heads and weekly vacuuming w/ PWCs can work well w/ SW fish. A floss filled HOB (toss carbon in to remove any meds, smells, off colors) or (better still) canister is a good supplement. I've used 1" coarse dolomite on top of a UGF & put ~2" sand on top of that w/ success in the past. I wouldn't try to keep gobies or blennies in a tank like that... stick to hardy species like damsels, chromis, some clowns, small wrasses or small predators (dwarf lion, hawks). Shrimp are OK... and probably the only inverts that will work w/o lighting and/or better water. Just be sure you won't be tempted to get into anenomies & clams later.

Ea week, when you do your pwc, vacuum the heck out of 1/4 to 1/3 of the sand, leaving the rest for future weeks.

[TropicalNorth]

I don't intend to have any corals or anenomies in the future (bit too much for me). I'd also like avoid a UGF, just not a fan.

Alright let me get this straight.
1. Skimmer is not essential for a 20G (this is the biggest tank I can do).
2. Weekly 25% water changes.
3. 1lb of Live Rock per gallon (20lbs for a 20G)
4. A pair of Ocelaris Clowns would be better than 1.

A few more questions.
1. Is it possible to have say 15lbs of Live Rock + decent mechanical filtration?
2. Is is okay if I use water straight from the tap (it is sourced from mountain streams so it is pristine)?
3. Would the Clowns have to be a male/female pair or would male/male or female/female be okay?
4. Would a double 18w fluorescent light with one bulb being 10000k and the other an actinic blue be a good option?
5. Damsel/Chromis/Small Wrasse would be a better option than a Goby or Blennie?
6. Does the sand have to be 'special' or is river sand okay.

That's all the questions I have for now (phew LOL).

[rbell219]

1. spend the extra money on the live rock. You haven't mentioned any other biological filtration which is more important in this case. You can suck up the waste weekly with your syphon and be your own mechanical filter. Plus your shrimp and snails will take care of it too.
2. Just test your source water. You want it to be free of everything..silicates, phosphates, metals, ammonia, nitrates, nitrites, you know the list
3. I'm not the expert here..some fish are better kept in same sex situations when there is only two. Maybe someone else can help here.
4. 36 watts total? Even 18 will be fine for just fish.
5. Yes
7. I've read a lot of people using play sand and a list of others---personally I wouldn't use anything but sand packaged specifically for aquariums. I definitely woulldn't take it straight from a river to my tank. If you;re talking about that---i'd sterilize it some way---maybe boil it?

[TropicalNorth]

Thanks.
My LFS has Live Rock (though it is expensive) so I guess I'll have to invest in 20lbs worth. I use river sand in my 4 freshwater tanks, just wanted to make sure it would be okay in a saltwater tank, chemistry wise. So Live Rock (and it's inhabitants) doesn't need any special/strong lighting.

[TropicalNorth]

Update. I just did a bit of research and found an online place that sells lights and bulbs. Being within a budget would a single 18w light support Live Rock and what sort or bulb should I consider; they have a 50/50 6000k/actinic, 10000k and day light bulbs. I think this will be the last of my questions (thank god LOL). Thanks.

[dorkfish]

Clowns are born withoout genders and they assume them based on dominance within the group (or pair) they are in, with the most dominant clown becoming a female, second most dominant becoming male and any other clowns remaining sexually immature until one of the dominant clowns passes away. Eg. if you buy two small clowns, you will eventually have a M/F pair.

If the price of live rock is an issue, you can go with a 50/50 or higher mix of live/base rock Instead of all live.

If the river sand is mostly inert, it should be fine for a saltwater tank. Aragonite however, is often the more favourable substrate, espescially if your going with a deep sand bed. I personally use pool filter sand in my tank.

For just fish only or fish only with live rock, only enough light for the fish to tell night from day is needed.

With damsels or chromis, you run a high risk of having aggresion issues between them and the clowns due tot he fact that there related and damsels can be preetty evil to other tankmates even if they are of a different family.

Usually, for asthetical reasons, you want about a 50/50 mix of actinic and daylight bulbs, so the 50/50 bulb would be the one to go with.

[rbell219]

I've been told don't go under 2 watts per gallon for FOWLR. I'm not sure if the live rock biological properties need it--I was concerned with growing coraline algae. If you don't get the response you're looking for, try posting a new thread with this question only.
IMO--it's worth saving the money and going with more lighting.

edited--see above post---there ya go<---18 watts it is.

[TropicalNorth]

Appreciate the help.
I'll probably do some more research and come back with a few new questions/threads. I've now got a budget now (my parents have agreed to make the tank conversion an Xmas present WooHoo :)).