steven@reev.com

with a large algae bloom, your test are going to show 0 nitrates due the algae absorbing it.

We need pictures. And facts. Saying "large water changes" and "good levels" doesn't mean anything to us, as we need specifics. How are you determining the skimmer is working "well"; how often are you cleaning it out?

Ok gotcha. my tank is 240 and my sump is 88, I did two water changes about two weeks apart. about 60 to 70 gallons each time. I empty the skimmer about one time each week but it holds about a gallon and a half of skimmage and it seems to be producing a decent amount of skimmage. the levels are as follows.
PH 8.4
Magnesium 1300
Kh 10 dkh
calcium 440
ammonia 0
nitrites 0
nitrates 0
phosphates are 0 to 5 it is hard to tell as the test colors are so close in shade.

You might have phosphate accumulated in your live rock and substrate, coupled with old light bulbs (my case, as I'm late in finishing my DIY LED fixture...).

this tank has only been setup since april.

Do you have any nitrate or phosphate removal system? For example macro algae in your sump, bio pellets, vodka dosing or (my favorite) an Algae scrubber?

I would check your newly mixed saltwater (and your RO water) for nitrate and phosphate. It could be that with every water change, you are adding fuel for the plants to grow.

How long are your lights on each day? Is sunlight hitting the tank even for a brief period? This is your 9th month with those bulbs, so they are getting close to needing to be replaced.

PO4 measurements: 0 is great. 5ppm is horrible. The difference in the test kit will be clear to dark blue (Salifert) and very easy to spot. Now if you mean .03 or .25ppm, I could see how it would be hard to judge. It is best to look at your test kits under daylight conditions, but not in direct sunlight. Just ambient bright daylight. The goal for most of us is .03ppm - it is possible to get a zero reading and have lots of algae that binds up the stuff leaving it undetectable. If you rip out a bunch, then test the next day you'll usually get a decent reading.

Pictures, please.

Ok, update. I bought a new test kit and it looks like my PO4 and NO3 are way off the chart. I am surprised as I thought the refugium was supposed to help prevent this. I have started the vodka dosing regeme as of yesterday and will let you know how it goes over the next few weeks.
my nitrate is about 40ppm and the phosphate is about 1.0ppm I know way to high! gees I thought I was doing a good job gees!
is there any kind of maintenance I should do for the refugium? I did not use filter socks for the last nine months. I just started last month, but the input for the refugium does not have a sock on it so the detritus probably collects in the sand a lot. I may not have a good design of my sump. I designed it myself but I never did it before. I will put together a drawing of it to upload. pictures would be had to get in that it is under my tank. it is about 88 gallons total.
thanks for all the input, and I guess I need to order some new lights. anyone have a good resource for lights? I currently have 250w MH 20K x 4 and 4 T5 actinic powerglo 54W. I would like to go to 400W or to LED's but both prospects will require some significant cash.
-Steven

Originally Posted by melev

I would check your newly mixed saltwater (and your RO water) for nitrate and phosphate. It could be that with every water change, you are adding fuel for the plants to grow.

How long are your lights on each day? Is sunlight hitting the tank even for a brief period? This is your 9th month with those bulbs, so they are getting close to needing to be replaced.

PO4 measurements: 0 is great. 5ppm is horrible. The difference in the test kit will be clear to dark blue (Salifert) and very easy to spot. Now if you mean .03 or .25ppm, I could see how it would be hard to judge. It is best to look at your test kits under daylight conditions, but not in direct sunlight. Just ambient bright daylight. The goal for most of us is .03ppm - it is possible to get a zero reading and have lots of algae that binds up the stuff leaving it undetectable. If you rip out a bunch, then test the next day you'll usually get a decent reading.

Pictures, please.

Do a 50% water change and your nitrates will be 20ppm the next day. Every time you do a 50% water change, you'll cut the nitrates in half. It's a lot of work, but it works. Vodka takes time - 12 weeks minimum. For my established reef, and because I was following the recipe to the letter, it took exactly 7 months until the nitrates came crashing down. I was very patient - and annoyed - but it does work.

For PO4, I'd use Phosphate Control. Dose it at night and skim the system & run the filter sock. By morning, PO4 will be 0.

For lights, there are a ton of options out there.

The only real maintenance a refugium needs is to remove some of the macro algae occasionally. That's how the nutrients are actually removed from the system.

The water changes marc recommends will get your nitrates down, but you still need some way to keep them down. That means keeping up with regular large water changes, or having some way to remove them continously.

what is an algae scrubber?

Originally Posted by Alaska_Phil

Do you have any nitrate or phosphate removal system? For example macro algae in your sump, bio pellets, vodka dosing or (my favorite) an Algae scrubber?

Short answer is that it's an easily removed screen with high light and water flow that grows algae faster than your display. Once a week you remove and clean half of it. There's a couple of us on this site that use them.

Here's a web site dedicated to them http://www.algaescrubber.net/forums/

Edit:
Here's a photo of mine from before it got a good coat of algae on it. You can see the full construction photo's in my album if you go to my profile.