Beginner with an established tank

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#1
I bought a house 8 months ago, and out of what the previous owners left behind, the saltwater fish tank is the most complicated to deal with. (The bed was a weird thing to leave behind, too.) I'm essentially a beginner, though I have learned a lot about basic things I need to do.

Anyway, according to the previous owner, this 29 gallon tank was started about 15 years ago with no plans to continue it for this long. He said the fish in it are 10 to 15 years old. There were two yellowtail damsels and two silver monos. One of the monos has since died, but all the rest remain. I added a lawnmower blenny about a month ago. This is a fish only tank, so that's good for a beginner, but I'm still trying to figure out what I'm doing.

When I started, the tank was pretty gross. The previous owner told me that there was no need to clean the tank because it would take care of itself. There was nothing to test the water with, and all of the decorations were covered in slime. I started by taking all of that out and cleaning it. I put maybe one third of it back in the tank, which helped a lot, but I still want to improve it.

Within the past few months, I have replaced the heater with a new one I trust more, and I now have a hydrometer, pH test strips, and an in-tank ammonia monitor. The substrate is coral gravel, and I have an AquaClear 70 filter in addition to an undergravel filter. (There's also some weird stuff in the closet that I don't know if I need.) Everything seems fine except that the pH strips show a "dangerous" level of nitrate. I was told by a pet store person to do a fifty-fifty water change to lower the nitrate, which I did, and I also took out all of the old substrate and replaced with the rest with what was left in the bag in two installments. The nitrate level is still dangerous.

Considering that this guy told me not to clean the tank, I have to imagine that the underground filter is quite dirty. It definitely works because when I have taken out the tube connecting the filter to its powerhead, the tube has been full of disgusting stuff every time. My concern is with the fact that the nitrate level is so high that even a fifty-fifty water change did not affect the level on the pH strip.

Should I take out the UGF and replace it with a new UGF, clean the UGF that I currently have, or use a different filtration system? Obviously the fish have survived this long with rough water conditions, but I hate to think that they are not as healthy as they could be.

Should I use a different type of substrate? I did purchase some live sand a few weeks ago but haven't used it since I realized I have a UGF. I have tried to look these things up online, but since my tank is already established, a lot of the beginner level articles don't apply. Since I don't know what I'm doing, it's hard to follow some of the other articles. I feel like the previous tank maintenance makes my situation different than the others I've read about.

Sorry for the long post. I wanted to make sure I gave the info that you guys might need.

Tl;dr: I have an established tank that needs help beyond what I understand, especially regarding filtration and nitrates. Here are some pictures of what I've done.

 

jay0705

Administrator
Staff member
#2
Welcome to saltwater. Do not replace the substrate. The stuff in it would wipe out an entire tank. You don't need an under gravel filter. Your hob is fine. Nitrate is the least of your worries. Ammonia is the thing to worry about. Get a good liquid test kit. Selifert or red sea are good. Api is better then nothing tho.
 
#3
I wouldnt change the substrate I'm suprised you didn't cause an ammonia spike when you did clean it I would get an external filter run that with the ugf and use a nitrate remover and phosphate remover in it that should remove the dirty look to the water and the high nitrate levels
 
#4
Welcome to saltwater. Do not replace the substrate. The stuff in it would wipe out an entire tank. You don't need an under gravel filter. Your hob is fine. Nitrate is the least of your worries. Ammonia is the thing to worry about. Get a good liquid test kit. Selifert or red sea are good. Api is better then nothing tho.
I had already taken out all of the old substrate and put in fresh stuff before I originally posted. (That old stuff was seriously nasty.) I figured that by not cleaning much else (just the glass) I would keep enough bacteria in the tank. Maybe I just lucked out, or maybe these fish just refuse to die.

I got a liquid test kit, and the ammonia level is zero. The only level that's off is nitrate, and it's still off the chart (at least 160 ppm). Should I take out the ugf? Unplug it for a few days to see what happens? It's noisy.
 
#5
I wouldnt change the substrate I'm suprised you didn't cause an ammonia spike when you did clean it I would get an external filter run that with the ugf and use a nitrate remover and phosphate remover in it that should remove the dirty look to the water and the high nitrate levels
By external filter, do you mean something like the AquaClear filter I have?

The water doesn't look dirty at all; it's just the nitrate level that makes me think it must be dirty. It was super gross and cloudy when I took out that old substrate. I used a fine mesh net to take out a large amount of greenish brown gunk.

What exactly do you mean by using a nitrate remover? Do I need live rock? Plants? A chemical?
 
#6
By external filter, do you mean something like the AquaClear filter I have?

The water doesn't look dirty at all; it's just the nitrate level that makes me think it must be dirty. It was super gross and cloudy when I took out that old substrate. I used a fine mesh net to take out a large amount of greenish brown gunk.

What exactly do you mean by using a nitrate remover? Do I need live rock? Plants? A chemical?
You can use a nitrate remover in the external filter its something you can buy to put in it also amquel chemical is very good at removing nitrate the new filter you bought have pipes that go outside the tank or does it sit inside the tank don't turn off the underground filter until you habuve got a big enough filter and it been going for 6 weeks while the ugf is still going
 

beaslbob

Well-Known Member
#7
Actually under gravel filters although old school work just fine.

I would not use chemicals to lower nitrate.

I do recommend adding macro algae which consumes ammonia (if present) then nitrates plus phosphates and co2 while returning oxygen and fish food. You may have to partition the tank so a small section is for the macros and the rest for the fish.

Actually, the previous owner was correct in stating to not clean up the tank. Removing the algae and slime removed the nitrate consumers balancing out and stabilizing the system. 30-40 years ago algae in a tank was considered to be a sign of a healthy tank and the lack of algae/slime was considered to be a sign of a tank that was too sterile. The key and hard part is to get a "pretty" (algae free) tank while still consuming the nitrates. IMHO the most effective method is to simple replace the ugly algae/slime with pretty macro algae or hide the algae/slime is a hidden algae turf scrubber.

I suggest you ask local hobbiests if they have some macro algaes. Usually they are tossing a lot each month and would be glad to help you.


best tank ever


my .02
 
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