Why are my corals not grow?

[chaos1907]

Hi everyone,

I have 10 years experince on this hobby and established reef tanks several times. I always interested about SPS in my hobby life. I was successful most of time about growing and staining also.

I made a new 90g reef tank at Oct'14. Since that day i live problem with my corals, even montiporas too. Bleaching, STN, not growing etc... I couldn't get satisfactory performance from my SPSs. So, I've changed my coral population from fully SPS to 50%SPS and 50% LPS. as you can see, I've got some SPS colonies from my older tank.

Please share your advices because, I'm about to go crazy

Here is the tank infos:
Salinity:1.025
NO3: 2 ppm
kH: 11
Ca:430
Mg: 1320
pH: 8.2
Po4: 0,19 (it looks like too high but..!?)
All values are stable...

Reactors:
PS: BK Double Cone 200
Biopllet reactor with AIO
Phosphate reactor with ROWAphos
Schuran Pico Calcium Reactor (it works on proper condition)

Lighting:
4x24T5+1x150W MH Giesemann Infinity

Stream:
2x Vortech MP40 with reeflink
Jebao 6000 DC return pump

 

[CommsTech]

I would say your PO4 is on the higher side. Mine usually sits around 0.03 - 0.06 and seems to be the sweet spot for my tank. I use to run my Alk quite high around 11 where yours is and I always had problems. These days I run my Alk closer to natural at around 7 and my tank is so much better. I think for SPS they don't like high Alk. Anything over 8 and they seem to become stressed. Perhaps try lowering your Alk slowly to around 7 - 8. Good luck

 

[Jim.mer]

Yup gotta agree, Try using GFO in the Reactor not the Phos, Yes the KH, the lower to 7 the better, It ties in all the molecules better, Your lights aren't enough to support good SPS growth, sure it's bright but you could really do with 250 mh

 

[chaos1907]

Great, thanks for your advices...

BTW, Is it enough to frequent water changes for reduce KH or is there any different way, what do you say?

 

[Savoie83]

For the phosphate you have and kh I would go with 5 ppm+ of nitrate or lower the phophate and kh a bit and feed the coral more.

 

[toothman]

Most salt has elevated kh, reef crystals are especially high. I guess it is what most reefers want. Try to keep you kh between 7-8. Anything higher does stress corals. When I do a water change I just turn the dosing pumps off for a day or 2 until kh is back down to 7.5. Really phosphate should be less than .06. Water change will reduce it as long as you have a decent ro/di.

 

[chaos1907]

I use Kent Marine because of potassium. I measured KH of that while water change it was 7. So, it seems ok. I suspect calcium reactor. Daily KH consumption of my tank is approximately 2 but reactor outlet is 58!? I know i must keep it around 38-40 according to that consumption. I need to reset my calcium reactor again.
Do you advice, what is the best adjusment values for Schuran Pico?
P.S: current adjusments; 80 bubbles in a min, 5 ml water every 10 sec with doping pump

 

[bogg]

Personally I think its your skimmer pulling too much
Also your kh is high ime keep it like nsw 6-8
I would do water changes repeatedly

 

[CHSUB]

interesting advice????

everyone suggests lowering alk....here is a study that proves elevated alk mitigates that adverse effects of high nitrates. in the cited example alk is 14 and no3 is higher than found on the reefs; similar to the OP. not so sure alk @ 11 is the problem? i run my alk at ~ 8.0, however. i might look at the bio-pellets as an issue?

OP, when you had success was it with bio-pellets?

Effects of lowered pH and elevated nitrate on coral calcification.
Marubini, F.; Atkinson, M. J. Biosphere 2 Center, Columbia Univ., Oracle, AZ, USA. Marine Ecology: Progress Series (1999), 188 117-121.

Bicarbonate addition promotes coral growth. Marubini, Francesca; Thake, Brenda. School of Biological Sciences, Queen Mary and Westfield College, London, UK. Limnology and Oceanography (1999), 44(3), 716-720.

 

[kevin_e]

The alkalinity is more than acceptable. A lot of people keep thier dKH between 10-12 without ill effects. The lighting is more than capable of supporting sps.

 

[CommsTech]

I think the high Alk high growth is an old school of thought. In my tank when I have high alk I have nothing but problems. Same with alot of other SPS tanks here in Aus. I think it stresses SPS.

 

[CommsTech]

If I raise mine I certainly have issues with my SPS. I like to keep my water as close to ocean values as possible. but I guess each tank is different.

 

[Reefer54]

I try to keep mine as close to the salt mix i use. Red Sea blue bucket.....this is really just so i do not have to worry about any fluctuation when doing water changes....keepin it simple is a must for me.

Without reading the above responses, my immediate thought after reading the original poster's question was alk shifts....my opinion, and this is after i ran my last tank at high dkh for a while, was that my sps seemed to be less forgiving of minor shifts in my alk when it was high, but their allowance for smaller shifts (<.2 shift) when i keep it at 8 seems to be like it never happens.....which it really doesnt these days. dosing and kalk were a pain to tweek, but getting them right has made a world of difference.....now if i could just get my wife to let me use the bath tub as a frag tank.

 

[chaos1907]

I have had my all from 9.5-11 at all times only my tank and the SPS are growing spectacularly. I thin this whole Alk too high is not correct, too many people jumping on that bandwagon these days. Where is the proof that high alk is bad? I'm not saying its right but I haven't had any issues whatsoever with higher alk.

yeah, i agree... when KH 11 then calcium should be 430-450 and Mg 1320-1330 according to ionic balance. So, my values are ok to this balance