what do I do?

[lynda orourke]

Hi

I am a toatl novice at fish keeping and a few months ago I was given a marine tank, to be honest I don't know what I'm doing with it.

Its about 25L and containes living rocks a clown fish, another fish I haven't been able to identife a snail and what I think are bristleworms.

It has a trickle filtatration system.

The guy that gave it to me said I that what I needed to do to maintain it was
-remove the black algue as it builds up
-top up with warm tap water as it evaporates off
-check the density
-rinse the sponge in the filter if it gets to cloged up

Having read up on marine tanks I am not convinced about his advise.

He also said that he had kept hermit crabs and shrimp in the tank but that they had died

what should I do next
-

[ccCapt]

The first thing that jumped out at me was ........ "remove the black algue as it builds up". I don't know exactly what black algea is. Maybe cyanobacteria? Can you take a pic?
What kind of water are you using to top off? It doesn't have to be warm. Room temp is fine since you are probably only adding a little at a time.
Density (specific gravity or salinity) shouldn't really change except for evaporation. What is it at now and how do you check it?
Where is the sponge located? It should be cleaned every couple days.
Do you have any test kits? It's good to know the tanks water parameters. Get some readings for ph, nitrate and alk for now.
How often are you doing water changes and what kind of salt do you use?

Are you have any major issues with the tank now or are you just looking for some general maintainence info?

[lynda orourke]

I am topping up with RO water at room temp, using tap water didn't sound like a sane idea. will do a chem check when I get home. sponge is in a copartment at the top of the tank.

I don't know how often I should be doing water changes.

No real problems with the tank the fish look healthy.

But I don't think the maintance i am doing with it is right.

[roka64]

I would buy a liquid test kit (the dip tabs aren't all that accurate). Find out where you stand with ammonia, nitrItes, nitrAtes.
Find out what the other fish is or post a pic.
Is the "black" algae brown, red or green?
I am assuming the sponge is in your HOB (hang on back) filter. If so, you should rinse it out when you do your PWCs (partial water changes) in the old SW that you siphon out of your tank. This will keep your beneficial bacteria alive.
You should do PWC about every two weeks or maybe even three. Pre mix your SW for at least 24 hours. Have a ph and heater in the mix and try to get the salinity and temp the same as your tank's.

[melosu58]

I would say the first order of buiness would be your water test results. That will point us in the right direction.

[Ziggy953]

I agree with Mike. Test your water and post your results in this thread and then we can go from there.

[lynda orourke]

ok water test results

Along with the tank I was given test kits for ammonia and nitrite both read <0.25ppm

I work in an analytical lab using the density meter here I get reading of 1.021 wt/ml @ 20C, and a pH reading of 7.2

Will try a little tank photography at the weekend

[Skyrmir]

I'm pretty much a newbie with salt myself, but that pH sounds really low. I'd be interested in the rest of the tests.

[Ziggy953]

Ok...your PH is very low. It should be 7.8-8.1, the closer to 8 the better. With ammonia in your water that tells me you are overstocked or under cycled. How long has this tank been in your care? I'm guessing it was moved when it was given to you right?

Your biological filter is not keeping up with your fish load. You have 2 fish right? How much LR do you have in the tank? What kind of filter is it that you are using? Does it have GAC or another media in it?

[ccCapt]

If you have ANY nitrite or ammonia it's too much. What is your nitrate? You may be having some die off and the tank is doing a mini cycle. I would do some 20% water changes every few days to get both of those to 0.
The density meter you used, is it made for saltwater? There are refractometers made for many different fluids and you can get false reading testing saltwater on a refractometer made for sugar, for example.
That pH can not be right. Nothing would be alive in your tank with a pH at 7.2. You can't take a sample of sw, transport it across town to your lab or to the lfs and get an accurate reading. As soon as the water is taken from the tank, the pH starts to change, usually going down in readings due to lower o2 level and higher co2.