Pale corals, low growth rates???

[lcheesman]

Hello, I was wondering if I could have some advice on a problem I have not been able to rectify. Pale corals...all corals really. Low growth. Lack of food...I don't know.

A run down on the set-up first.
300 gallon all glass 72x30x30
3 x 250 watt 14k, 2 x 140 watt actinics, 2 x 58 watt actinics, halides less than 6 months old
turnover 25,000 lph plenty of laminar flow and tubulance
ph night day 8.0-8.2 a bit low I know
kalkwasser dripped nightly
aquamedic clacium reactor ph 6.7 effluent 2 drops per second, reactor media currently ARM
calcium 390ppm
dkh 11
salinity 1.025
phosphate 0 with deltec/merck test ket
nitrite 0
nitrate 0, cant seem to get this to even a few ppm
skimmer deltec ap850
orp 360+
ozonizer 100mg delivered through skimmer
strontium approx 9ppm
fish 14 small to yellow tang size
corals around 25, sps 60%, lps 40%
water changes 20 gallons every 2 weeks Reef crystals
Kent marine 4 stage ro filter tds reads maximum of 3
kent-marine organics resin
feeding 1 cube of artiemia daily + cyclops-eez
sps corals top 1/2 of tank
rowaphos used continually in reactor
live rock around 150 kilos roughly
2 inch sand bed, fine sand

Almost all corals are always pale, tissue is thin, lack of symbiotic algae I think?, sps always seem pale with little polyp extension, corals lack real growth, sps corals seem to never base down properly receeding from the base upwards sometimes, mushrooms are small and very thin almost see through, corralline algae seems to grow to about 1 penny (1 cent) size and start to receed from the center. Have I a lack of nitrogen or fertilizer for the symbiotic algae. There is just a real lack of vigour. I have a stylophora which grows more like a birds nest coral, very thin the upper branches show very little polyp extension although the parts in the shade on the underside seem nice and rich in colour and extend much more. I have a a few lobophyllia corals which seem pale also. Something is amiss and I am very baffled. I made 2 x 20% water changes. Do I need to up feeding?apart from the low ph, the parameters and maintenance seem a great recipe for reasonable success. Lost for ideas and after so long running out of patience.

Any help would be very much appreciated.

 

[Lpsfanatic338]

Probably Bleached

 

[kirstenk]

Looks like a low nutrient tank. Too Low. Two suggestions. You did'nt mention how long you run your MH but you might try cutting back 1/2 every couple days until you see some improvement. Secondly, feed more. Your fish and LPS will appreciate it too. I have read many threads where doing these two things helped improve the coloration on their SPS.

 

[cwegescheide]

Ya know, I'd tripple check your salinity and make sure your method of measurement is accurate. The reason I say that is because I sortof noticed my corals not looking as good as i thought they should and didn't know why... For a LONG time i've used a refractometer thinking NO problem it should be dead on and I was reading 7ppm high. So when I thought my salinity was 1.025 it was actually 1.018 I've corrected the issue about a month ago and I donno if its a coincedence but i've noticed an increase in growth/encrusting recently.

Chris

 

[lcheesman]

Excellent ideas guy's I will try all of them. Metal halides are on for 9 Hours? I will double check the accuracy of my salinity measuring devices.

Do any of you think the lighting is excess. Only the stylophora is right towards the bottom of the tank....pretty deep and is showing the same lack of growth colour?

Thank you all so much for your help thus far.

 

[ri]

Is it possible to provide a pic or two?

ri

 

[lcheesman]

Yes, I will post a pic or so within the next day.

cheers

 

[lcheesman]

Ok, I've put 4 pictures in my gallery. You can see how pale they are.

thank you

 

[lcheesman]

Ok, so has any one have any other ideas?
Is it possible it could be too much light too long a metal halide photoperiod (9hrs). There are patches of turf algae in this tank although phosphate and nitrate is 0, could the tank still be starved of nutrients?

 

[MCsaxmaster]

They do look bleached. What is the temperature? Aslo, maybe double or triple check this with another thermometer, just to be certain.

Chris

 

[lcheesman]

Temperature is between 25c and 26.4c. The tank has a chiller and 2 digital meters?

 

[lcheesman]

This picture shows the problem better. You can see the inner shaded part of the coral has extended polyps. The outter part is very poor. This coral is 18 inches deep in my tank. I have measured the lux output of my bulbs 12 inches below the bulbs (unable to measure in water) it reads approx 32,000-35,000 lux and the tank does look very bright. Photoperiod for MH is 10 hrs.

I am very grateful for everyones input.
In any ones experience would this be a cause?Not just the one coral either, most are pale. As you can see the coral now has algae growing on it's branches as the tissue has receeded over a lengthy period in the condition.

 

[MCsaxmaster]

What occured when the corals bleached? Did you have them and grow them for a long period and all of a sudden they began bleaching, or have they looked like this for most of the time you've had them?

For now, shade them (maybe with some screen/clothe), keep water flow strong around them and use a small, particulate food. Oyster eggs from DT's would probably be good for this application, or meaty food in a blender--you want microscopic particles.

Chris

 

[lcheesman]

Thanks Chris,
When I first get them they were ok for a few days then the colours seem to pale and polyps don't extend as much. I am also of the opinion it is too much light. I have started feeding a mix of cyclops, cylop-eez, artemia, mysis, zooplex, chromaplex, flake foods etc that I blended. A 1inch cube per day...plenty of particulate variance what do you think?

I have shaded this coral and within 8 hours I can notice more polyps out and a slightly darker colour. Every one said I need loads of light for this size tank. My 250 watt lights seem brighter than most 400watt single ended I have seen. My old aquarium 100 gallons had 2 x 150 watts and everything thrived. I have 1 acropora staghorn type positioned about 3 inches below the surface and the colours are a nice neon blue, but that is about the only coral that likes it.

Should I gradually decrease the photoperiod as suggested in an earlier post. Perhaps to 6 hrs of halide, perhaps raise the lights gradualy also?

 

[MCsaxmaster]

This might be a silly question, but do you have UV-absorbing shielding around the bulbs?

Looks like they are getting more light than they are used to. This is not to say "too much" light in general, however. Many acroporids and pocilloporids can and do grow in inches of water in blindingly bright light--much brighter than what you have. Corals transplanted from 20 m depth to this level (or even to 5 or 10 m) bleach quickly, even if the corals in question are the same species. If they are slowly acclimated to the new, brighter light levels they do fine though. The problem here was probably inadequate (or a lack of) acclimation to a new lighting regime. The light probably is not too bright for corals acclimated to it, but very well could be too bright for corals accustomed to dimmer lighting.

Shade, feed, and keep the water flow strong. I wouldn't necessarily mess with photoperiod. Shading is much more effective IME.

Chris

 

[lcheesman]

The bulbs have uv lense covers yes.

You know I think your right about the acclimitisation, not lack of but perhaps not understanding the full effects of the bulbs.

Although I'm not sure what sort of shading to use?

 

[Boat Racer]

I have read and through experience that less photo period will probably be best.I run my MH from 11:00 am - 5:00 pm.My corals seem to extend very well and open up with the light.

 

[MCsaxmaster]

For shading I would use some window screen or something similar. That will cut light levels significantly. Also, raising the lights by 20 or 30 cm can have the same effect (inverse square rule) in reducing the intensity on the corals.

Again, I don't think reducing the photoperiod is necessarily the answer. In fact, it doesn't make much sense to me to have less than a 10-12 hr. photoperiod. Granted, it may not be necessary to have metal halides on for that full period if a bunch of VHO's or something are also on the tank, but there haven't been any studies to determine the effects of alterred photoperiods on corals that I know of (they range from 11.5-12.5 hr/day in nature) nor are the lights used over most people's tanks bright enough to cause photoinhibition in high-light adapted corals if the corals are at least a foot or so from the bulb (in most cases anyway). So again, I don't think messing with photoperiod is beneficial nor the answer.

Chris

 

[lcheesman]

Ok, Thank you all for you help. Most appreciated I will raise the lights and gradualy lower the photoperiod. I really don't fancy using shading so I have already moved the lights up 2 inches.

Thank you all for your help

 

[lcheesman]

Ok, Its been a few weeks after raising the halides about 10 inches.

The corals are still not rich in any colour, be it red or brown or green. There is an improvement in but it's not huge. An acro that is at the very top and was very light blue has now turned to a VERY light brown. Corals still do seem very pale??

What else can I try?

Nitrates are completely 0?

I need some more ideas.