I am hoping someone has an idea that I haven't thought of with this problem:

In brief the parameters are as follows:
Nitrate between 2.5 and 5 ppm
Phosphate <0.1ppm
Calc 410 mg/l
Alk 3.66
Mag 1140 which is a little low prefer to have this up around 1350-1500 but I don't think this level is detrimental.

I use RO water mixed with reef crystals.

The tank is 255 litres with an upflow sump measuring 33" x 6" x 9" this contains a DSB that is about 6-7" deep above this I have caulerpa growing which covers the DSB I remove half of the caulerpa when the water surface is completly covered and I remove it from alternate ends to keep it as fresh as possible this is lit 24 hours a day by a single marine white flourescent T8. The over flow weir has a bag of phosphate remover in it.

The main tank also has a deltec mce 300 skimmer and I utilise an eheim 2215 to run an 8 watt UV sterilizer the eheim has no media in it. It also has a couple of powerheads the water turnover rate is about 25 times per hour.

It also has 30 kilos approx of premium and ultra grade live rock from stm the tank has been running for over 7 years but in its current set up for about 3 years. Prior to this it ran with a fluval external with ehfi substrat I'm sure you can imagine how demanding nitrates use to be. When this was removed the upstream sump was added. Nitrates ceased to be a problem within 2 months even on a test run I managed 6 months with out a water change as a test of the effectiveness, it was monitored very closely! Nitrate peaked at around 10-15 ppm if I remember correctly.

It is lit by 2 150 watt metal halides for about 7 hours a day the bulbs are 50,000 k and are about 9 months old.

Stock consists of the following:
80 micro dwarf blue leg hermits
a few red leg hermits
6 black foot turbos
1 cleaner shrimp
3 true peppermint shrimp
1 serpeant star
1 blue linkia
A couple of corals button polyps and mushroom nems etc
1 Coral Beauty (about 7 years old)
1 Fox face
6 neon chromis
pair banggai cardinals
pair black percs
1 pyjama wrasse

I am going to add some giant turbos and I am also going to get some gubbins to convert a maxi jet pump into a stream pump so I can have 2 stream pumps in the tank instead of the one I think that will up my flow rate by about 7,000 lph. This will give me a tank turnover rate of about 50 times per hour!!!!

Does anyone have any ideas and I'm not stocking a tang I don't have quarantine facilities and last time I got a tang I had an Ich out break the only survivor was the coral beauty. I like tangs to look at but I don't like keeping them!!!!!

Are there any grazers you can suggest invert or fish or am I missing something obvious?

Maintenance regime is a 15% water change weekly to maintain calc and alk and dosage with kent super dkh and seachem pro calcium as needed. Every couple of months half of the caulerpa is removed or when there is insufficient room for growth plus phosphate remover is replaced approx once a month or when phosphate levels start to climb. Periodically I also throw a bag of carbon in to remove organics but I prefer not to leave this in too long.

Cheers in advance of all of your help.

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Alan

Thweeerp!

I have tried to put this in three times so far here we go again.
hair algae needs 3 things to survive light, nitrate and phosphate,the reason your phosphate reading is so low is because the hair algae is consuming it.(are your test kits accurate ),starve it of any one of these and it will die . to get rid of my hair algae I bought a sea hare and a couple of cerith snails to get into the the spaces the sea hare couldn't. you can also use mithrax crabs they will eat it but will probably have a go at your inverts and small fish as well.another way to get rid of hair algae is to increase your ph to 8.5-8.6for a couple of weeks I had my ro water checked the other day prior to adding salt result 30ppm ahhhh but hair algae still under control.

I have a suspicion that the hair algae is trapping its own food and therefore whilst phosphate in the water is okay the algae has its own personal source!!!

I am going to up the number and variety of grazers as well as the flow rate so hopefully that will fix it.

My RO product water has a TDS of about 3.

I forgot to add that I have a sea urchin in there too which is effective when it gets to a rock with hair algae it just doesn't move around enough seems to be happy going around the same bunch of rocks for months on end it only goes at one end of the tank. I'm thinking off getting another one to put at the other end of the tank in the hope they will have one end each weird things urchins!!!!

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Alan

Thweeerp!

might be ya lights need changing or cut ya lighting down to 10 hours a day ....just a thought as everything else sounds ok alan..strange

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There's 3 sides to every story ...yours...mine,,,,and the ...TRUTH

The tank is lit 7 hours a day as it is don't want to cut it back any more.
I thought it might be the bulbs but they have only been in 9 months so shuld still be okay.

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Alan

Thweeerp!

what size tank is it,255ltr is too small for a big fish like the foxface(they are huge polluters)they ****e almost constantly,the low po4 reading is misleading as the algae is absorbing/using the po4 therefore the reading is what the algae cannot utilise therefore the algae will grow until it exhausts the po4 then sit at that level consuming the po4.reduce the bioload get the po4 and organics down the the algae will subside.hth mikk
p.s tang is not suitable for your tank they need more room mate.oopps re-read post you are not getting a tang.

I see what you are saying about the fox face but it is small as with all the other fish.

The hair algae problem is not filling the tank it is just in a few areas it is not a major problem just an annoying one. The real pain in the back side is that all the grazers go around the hair algae the rocks are spotless next to it!!!!!

Are there any grazers you can suggest obviously inverts as I do not intend to add any more fish although thinking about a red spot flymo goby!

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Alan

Thweeerp!