Dealing with dust algae

[604reefer]

Hi all,

I'm dealing with a dust algae issue that seems to be getting worse or at least steadily bad. This is just 2 days of buildup. The door in the background and windows surrounding do not let any sunlight hit the tank.



This spot I let build up a bit to see, looks pretty brown.


I've been googling and there seems to be no consistent advice to deal with this. The suggestions I've read range from lights out for 3 days straight to letting it grow for 3 weeks then remove with a big WC.

I'm only 4 months in on this tank, 1st SW tank. It's a 20g, "wild wild west" tank - no sump, no refugium. I have a hydor slim skim nano and eheim 350 surface skimmer.

Inverts:
- 14 snails (mix of cerith/astrea/margarita)
- fire shrimp
- rarely seen emerald crab
- 9 hermits

I do a 20-25% WC weekly. Temp is 77F, 8.3 PH, and always 1.025sg. I've cut back on feeding to 1x per day from 2-3x when I noticed last week nitrates were around 20ppm.

My coral (euphyllia/discosomas) and fish all look happy except for the torch with a mood that seems to change like I change my underwear. This could be because it was splitting from 1 skeleton to what is definitely 2 and maybe 3rd coming.

Do I just need to clean every other day and wait it out or is this not "new tank syndrome"? Should I consider that I've overstocked this 20g with my 4 fish (clown x2, chromis, blenny) and crew?

Thanks for the help.

[gregzz4]

What is your current NO3 and PO4?

[604reefer]

Originally Posted by gregzz4

What is your current NO3 and PO4?

No PO4 test kit , NO3 20ppm before WC and 5ppm after by the looks of it? Always hard to tell with the API kit and my eyes...

[Frogger]

Originally Posted by 604reefer

No PO4 test kit , NO3 20ppm before WC and 5ppm after by the looks of it? Always hard to tell with the API kit and my eyes...

If you are reading detectable nitrate with the API kit you do not want to be adding nitrate to your system. At this stage you do not need to buy the Red Sea Pro Test kit as the API is fine for high levels of nitrate. Red Sea Pro is required only for testing low levels of nitrate below 2ppm. Your money could be used better elsewhere.

You need to get a good quality phosphate test kit and determine what your phosphates are. Never add nitrates or phosphates to your system without knowing what your parameters are and without having a specific goal.

Depending on what your phosphates are you may want to add a nitrate reducing system of some sort, you may need to add a phosphate reducing system (GFO) and more importantly look at your husbandry of your tank.

[tang daddy]

Just get some clams that will solve nitrate problems... brightwells has no3 brick aswell.

[gregzz4]

Originally Posted by 604reefer

No PO4 test kit , NO3 20ppm before WC and 5ppm after by the looks of it? Always hard to tell with the API kit and my eyes...

Keep up with your current WC schedule and see if you can get your NO3 to near undetectable levels. I'd not worry about a quality test kit for now, but instead get a quality PO4 tester.
And ya, adding a Nitrogen source at this point is not recommended. I only brought it up as an option IF your levels started mimicking mine.

[philg3]

Honestly try to just ride it out. I just started a 20 gallon tank about 4 months ago, so I'm around the same stage you are. I've been battling diatom blooms for the past 2 months, but from previous experience this is just a growing pain. Turning out the lights for a day helps if it's gotten out of control, but besides that just get a good mag float and clean the glass daily. Clean the sand bed with water changes.

One thing I've recently tried is LESS water changes. I was doing about a 25% water change weekly, and would always have a big diatom bloom afterwards. I was away last weekend and didn't do a water change, and the diatoms have actually slowed a lot, like almost negligible. This could be a caused by a couple of things;

From what I've read Diatoms need silicate to form, and every time I do a water change i kick up a whole bunch of sand. I probably could have been way more vigilant about rinsing the sand before i started the tank, so every time I'm trying to clean the tank I'm actually kicking up a bunch of stuff into the water column including a bunch of silicate from the sandbed (correct me if I'm way off here).

Also, I've got an RODI that's always read 0 TDS, but it's probably 5 years old and likely the DI resin has expired. I've read that with the DI expired you could be adding a bunch of silicates to the tank through the water change and top off water. Just something else that might explain why i always have a diatom bloom after a water change.

Either way my advice is not to do anything crazy at 4 months because you're having a diatom bloom. Don't start dosing vodka or doing anything drastic. Obviously a bigger skimmer always helps, but maybe just try lights out for a few days and pushing the water change for a week and see what happens.

[604reefer]

Some great advice, thank you!

I ended up ordering the dual NO3/PO4 red sea kit as it works out to only $17.65 for the NO3 if you're already buying a PO4 kit and it got me to free shipping which saved an extra $8.95.

Once I figure out the PO4 level I'll report back. I was just starting to go a bit crazy cleaning every day with the mag float and toothbrush lol.

[Myka]

Originally Posted by gregzz4

What is your current NO3 and PO4?

Ditto.

Looks like diatom algae. Not a big worry, but a sign of overfeeding/under cleaning usually.

[gregzz4]

To elaborate on Myka's post ...

I find I get your kind of dust algae when my NO3 and PO4 are out of balance.
A recommended 'ideal' balance is around 1ppm NO3 and 0.03ppm PO4.

I never used to worry about these #'s, but found I was having issues with my PO4 being high and my NO3 always being 0.
After reading a post from ryanerickson about boosting Nitrates, I looked into it further. Then I proceeded to damage my corals by adding Nitrogen at a level too high and too fast, which caused my PO4 to crash.

I'd recommend you try adding a 'very small' amount of an NO3 source, such as Seachem's Nitrogen, and see what happens, per se.
Start with about 20% of their bottle dosage every other day, and test/monitor things.
Test daily to track what levels of Nitrogen addition affect your PO4 without completely reducing it.

DO NOT add too much Nitrogen quickly if you have corals. This will guarantee a crash in your PO4 level and result in some/all coral deaths.