bump

suggestion
 

Looking at your last reading, I might suggest you bump the salinity up to 1.023. One question I have though is what type of salt are you using. I was told by another reefer that for reef tanks he found that TM worked best for him. Less dosing was one of the benefits he stated. I am going to try it next time but right now I am using IO in my 72g. I did have a hair algae issue a little while ago and in my case narrowed it down to overfeeding. I didn't think I was at first but after looking at how some other reefers fed their tank I determined I was. I seem to have it under control as in the last 2 weeks it has virtually dissappeared. I also used rowaphos in my aquaclear 500 as well.
Hope this helps.:)

Are you doing a hyposalinity treatment on your system? If you aren't I'd bump your SG up to 1.025-1.026, assuming you have inverts, its from what I've read is the best level for them.

I am using IO salt. How much/often do you feed? And how much/often would you feed a 10g tank with 1 clownfish, corals and a bubbletip anemone.

I am not doing a hyposalinity treatment, that is one of the safe levels that is shown on my crappy little hydrometer, so thats what I have been keeping it at.

Its up to you where you want to keep your SG at. I just read and was told that 25 & 26 are "optimal" for inverts like shrimp. 1.021 I believe is a midpoint in hyposalinity treatments.

Take a look at say reef keeping magazine, and maybe advanced aquarist for more info on SG and make a decision from there.

feeding
 

I feed twice a day. I use a baster and squirt a tiny bit into the anenome that I have, and into my sun corals. I also just put a tiny bit in so the fish can get it. Everything seems fine. Even the fish seem ok with this. I have a 72g bowfront with a sailfin tang, a foxface, a couple of percs, some stupid chromis's that I used to help cycle the tank and cant get out now. 2 manderin dragonettes that are fat and happy and a sea hare[newest addition]
I think tou said you tried a seahare but it got sucked into one of the powerheads? I had this problem with an anenome and seemed to have remedied it by cutting and fitting some filter sponges around the inlets. So far so good. In a smaller tank it wouldnt take much to spike the phosphate and unfortunately even a test kit cant pick it up as it absorbs into the rock. The water may read zero's but the rock may have tons in it and with regular water changes and rowaphos or a phosban system it will decrease over time. One more thing..with feeding. It would have apeared to me when I started my reduction in the amount I fed all the fish wouldnt have enough food. I thought that with all the filtration I had in my tank it would absorb any excess amounts..it didnt. Forgot one other thing. What type of cleaner crew do you have..just snails??

Right now I only feed around 3 times a week. Usually a pinch of formula one flake or a tiny bit of frozen mysis that I pre-soak to thaw. I baste the mysis like you do and squirt it into the anemone. I really dont think I am overfeeding at all.

My cleanup crew consists of around 6 ceriths, 2 astea, 1 turbo, 2 sand sifting snails, and 4 blue leg hermits.

I also run a hang on back fuge filled with live rock and chaeto.

Hydrometers are notoriously inaccurate. You should calibrate your hydrometer as it is very likely that it is not reading right. Mine reads 0.002 lower than what the salinity actually is. Now that I know this, I am able to keep my tank's salinity where I actually want it! I keep my tank at 1.026. Your tank at 1.021 is very low. I would suggest raising it up to 1.026 which is the average salinity of the world's oceans that our critters come from, and also the most common level aquarists keep theirs at. :)

Here is a link to calibrate your hydrometer: http://reefkeeping.com/issues/2004-06/rhf/index.php

Holy wowzers!! This may be your problem. The cleanup crew also give off waste. They may eat algae but they also poop!! You have more clean up crew in your 10g than I do in my 33g. I would suggest you cut this down to maybe 1 Cerith, 1 Astraea, 2 Nassarius (I'm assuming this is what you mean by sand sifting snails?), and 2 hermits. Although I would think that 2 hermits and 1 Astraea are likely to be able to keep a tank that size clean. I would take the rest to your LFS. The Turbo in particular is a huge dumptruck of poop.

This is what has always confused me. You see in many places that it is recommended that you have 1 crab per gallon and 1 snail per 1/2 gallon.

I have always found this to be extreme.