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On-going issues in my 20 gallon reef


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I seem to be having mixed success with my 20 gallon tank. I don't have nearly as bad a hair algae problem as I did, although whether that is from the 25% water changes I am doing every week or the lawnmower blenny I added, I'm not sure.


Currently here is what the tank is stocked with:


1 Pulsing Xenia

1 Devils Hand leather

1 Duncan


1 Kenya tree

Assorted mushrooms, palys and zoos


Fish in the tank are 2 false perculas, 1 6 line wrasse and 1 lawnmower blenny. I am probably at the limit of fish stocking and don't intend to get any more. I would like to add one other small fish like a Royal Gramma or another small goby, but I think that would be pushing it.


I have 96 watts of t5 HO lights, I'm currently running a 12 hour photo period so maybe this is the problem with too much algae? I want to try cutting back to 2 hrs dawn, 6 hours mid-day, and 2 hrs dusk and see if this helps. Right now it is more like 1-10-1 or 2-8-2.


Other than adjusting the lighting, do you guys have any recommendations? I run a skimmer and do 25% water changes weekly, but still seem to have problems with nuisance algae. I don't feed more than once every other day. I use RO-DI water. Salinity is usually 1.23 to 1.25. I dose with Kent Marine iodine when I do my water changes. No kalkwasser or anything else. I haven't done tests for Nitrate, Nitrite or Phosphate recently but the last two times I did them they were either very low or undetectable.


Most things in the tank seem happy, but it seems like I have really bad luck with leathers. Virtually every leather I put in there dies. The devil's hand looked really good for the first week but now doesn't look too perky. It is not sloughing, at least. I had a Kenya tree that collapsed and is coming back.


I would post a pic of my tank but will have to wait til after work, I won't have time to do it before work.

I guess what is bumming me out about my tank right now are the lingering algae issues (much improved, however) and the fact that there is not much color in the tank. Everything is some shade of brown or pink right now (the mushrooms I have are not really visible yet).



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Drop the light a bunch for a couple days then even it back out. Id say 1 hour dawn and suk, 6-7 hour day. Thats hould be your usual cycle. Id cut it really low for a couple of days. Add some additional clean up grew to assist, and if your not all ready, add some chemi-pure elite, and purigen as this will buffer the water and assist as well. I used these steps on my last algae/diatom bloom, with a 10% water change every day for 3 days. The issue was completely solved at the end of day 3. I hope this helps, and happy reefing :D

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Something is out of whack if you are having problems with leather corals. You say the mushrooms aren't visible yet? Nuisance algae is one thing, but nuisance algae and poor coral health tells me something is off. Toxins, water quality ...

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If your corals are turning brown that is an indicator of elevated nutrient levels., Zooxanthellae algae feeds off of nitrates and phosphates and result in an increase in brown pigment., If your testing low levels it is because the abundance of nutrients are being consumed by them and the other algae in your tank.,


You need to figure out where theyre coming from., usually from dead spots gathering waste., or too much food that is built up and rotting., Or it may be something as simple as your rock work leaching phosphate.,


If you dont already I would recommend running some kind of phosphate media GFO, phosban, chemipure whatevers.


Also., How old are your bulbs?., Lighting for corals is more dependent on color spectrum rather than intensity., If your bulbs are getting old or you went cheap on them they may be shifting to more of the yellow/reddish spectrum of light rather than the blue light that corals need to conduct photosynthesis., An abundance of yellow/red light will cause corals harm and increase algae growth.

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Well, to be fair, most of the stuff was brown or pink when I bought it, with the exception of the kenya tree which I think was purple-ish.


I used "live" rock that I had in storage for several years, so it was dry and of course everything on it was dead. I put it in a vat of water and bleach to try and get rid of any organic stuff that might be on or in it that would decay when I put it in the tank. I suppose it could be leaching phosphate or something. Last time I checked, though, my phosphates were low. Would the corals be using those up directly?


I use RO/DI so that is not the problem. I feed sparingly.


I can't really get rid of my rock. I suppose I can, but I don't have money to buy all new live rock, even buying base rock and seeding with a small amount of live rock would be tough to do right now.


How would I go about finding if the rock is the problem?

The bulbs are maybe a year old, they are the ones that came with the fixture so may not be anything special.

I can get new bulbs. Are coralife ok? I can afford $15 a bulb or so, but $30 is out of the question. At that price I'm almost better off thinking about LEDs. After 4 years of buying bulbs I'll probably be at the price of a DIY LED system, less if you include the cost of the fixture I have now. a


And yes, I know this is not a cheap hobby but after spending so much on everything else I try to economize where I can. But if it means getting new bulbs so I stop having problems, then that is what I will get.

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I used "live" rock that I had in storage for several years, so it was dry and of course everything on it was dead. I put it in a vat of water and bleach to try and get rid of any organic stuff that might be on or in it that would decay when I put it in the tank. I suppose it could be leaching phosphate or something. Last time I checked, though, my phosphates were low. Would the corals be using those up directly?


Not sure if this is the problem or not. But bleach will only kill the organic stuff on the rocks. It will not remove it. For that you needed to do a muriatic acid bath. I just bought 30# of Pukani rock from Bulk Reef Supply and will have to do this as well. If not then all that organic stuff will decay and cause problems. This all depends on how much organic matter is on the rock and how long you let it cure or cycle in your tank. I'm a first timer on this so I don't know for sure but if this isn't fully the issue it may be contributing. Good luck. I hope you figure it out.

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Deleted User 3

You have 2 clownfish, a sixline and a blenny in a 20 gallon? The sixline is too big for a 20, let alone with three other fish, and I think 2 fish is the 'max' almost for a 20gallon, you could get away with a smaller fish in there with the clownfish, like a green clown goby (1.5" max). You probably have too many nitrates that are feeding the algae, what are your levels?

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The six-line is pretty small, maybe only 1.25" long. Clowns are each only about 1.5" long, and the blenny is 2 or 3" head to tail. I don't think they're all fully grown, I know I've seen bigger clowns but these aren't anywhere near that size.


I figured I would be safe at 3 or 4 gallons per fish. I know that the "gallons per fish" rule is kind of archaic and that, say, 12 1 inch damsels are not the same as 1 12 inch grouper.


I had a wad of chaeto that would grow to basketball size every week or two and need to be trimmed. Since I switched to RO water it hardly grows at all. Around that time is when I started getting the hair algae problems.


I thought I would be ok with 4 small fish in that tank, since people say that 1 or 2 fish in a ten gallon is fine.


I will run a test later for nitrate, nitrite and phosphate and post my results.

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Eh.,,. The only problem youve got as far as fish are concerned IMO is the wrasse., As it gets bigger itll get aggressive and need more room to stretch its fins., The clowns and the blenny with be fine in there size wise., As far as the algae concerned., Consider it free food for the blenny for now., Eventually the algae will die out and youll have to supplement it.,., How long has this tank been running?

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Well, I can move the wrasse when I need to. I have a vacant 55 that is not set up right now that I may eventually set up as a fish-only saltwater tank. So, when the time comes he will most likely go in there. I don't think I have the energy/time/money to keep up with a 55 gallon reef at this point.


I just checked phosphate and nitrate, nitrate shows as 0ppm (or close enough that I can't tell with my API test kit) and phosphate is either 0 or .25 ppm (hard for me to tell, based on color) could be somewhere in between.


I can try cutting down the light and see what happens. The 20 percent weekly changes with RO/DI water seem to have made a difference, at least the algae is not over-running the tank like it was. Of course, Mr. Blenny may have something to do with that as well :)


I will cut my light down to a 8-9 hour photo period, max. I'll see what happens with that.


I honestly don't know what it is with the leathers, maybe I've just had bad luck? Or maybe the place I'm getting them from has given me diseased stuff? All the leathers I've bought that have had problems have come from the same store. Currently the devil's hand looks ok but it doesn't seem anywhere near as perky as it could be, like it is not expanded fully. Guess I will have to wait and see. At least my Duncan is coming back since the anemone (which has been removed) crawled all over it.


My red mushrooms are doing well and even reproducing. I have a blue and green muchroom that are kind of small right now but I think will expand more, given time. I only moved them into that tank a week ago, and didn't really bother with acclimating them.

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Here is the plan I've come up with:


1. Lower daylight to 8 hours

2. Going to add nitrate and phosphate remover as well as carbon to a canister filter (with now bio media).

3. Take some of the dry rock I have, put it in a small bucket with some saltwater and let it sit for a while, then test for phosphate to see if it is leaching phosphate.


I think for now the first 2 items will give me immediate results, the last is the only way I have to determine if my current rock is leaching phosphates.

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Thats all fine.,. But remember if youre using a canister filter you will need to clean it thoroughly at least once a week., If not the trapped waste in there will rot., produce more nitrates.,., and youll just be spinning your wheels. Good luck to you ;)

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Yeah, that is probably not going to happen. I removed the sponges and ceramic bio rings, but it would probably still be a problem. I don't trust myself to keep up with taking that thing apart every week.


Would an AC 70 or AC 100 be better, then? If so, what is different with the design that it would not trap waste?

I would prefer to get an AC 100 since it seems there would be more room to have it as a fuge, but the local LFS is charging close to $80 for one. The AC 70 is cheaper. I have seen them for $55 and $35 online, respectively.

I don't know that my tank can wait a week to put the nitrate and phosphate media in. Would an AC 70 still have enough room to house a cheato ball?


Thanks for your input.

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