Help with bleaching SPS

[cmiller]

My SPS (several birds nest colonies, miyagi tort) in my 28 gal nano started bleaching about two weeks ago (at the SPS tips initially and in the past three days I noticed worsening bleaching at their bases). Lighting is LEDs 25 x 3 Watt – 14K; Dawn/Dusk – 4 x 3 Watt; – Actinic/466nm. Flow is good with Vortec mp10. Tank established for 9 months and prior to recent bleaching the SPS we're doing great and doubled in size in 6 months (to colonies about the size of baseball). My frogs spawn, zoas, open brain, monti, ricordias are all doing well.

For the last 6 weeks my Alk has fluctuated between 7 - 11 and CA floated between 340-410. Mg has stayed betw/ 1410-1450 and 0 Nitrates. No drastic changes to temps ( except for 2-3 degrees one warm day up to 82 from 79) and spec grav stable at 1.026. I've been doing 20% water changes 2x/month (kent marine reef salt mix). I've been dosing 2-part B-Ionic to try and stabilize Alk (at 11 ideally) and CA (ideally at 400). I was adding about 20ml of Alk and ca daily for about 10 days before I notice the bleaching. I slowly poured the Alk and ca additives into a high flow area of the tank. I also dose cap of iodide 3x/week, 7-10 drops of phytoplankton 4x/week. I thought perhaps dosing the Alk directly into the tank may have floated directly onto the SPS and caused the bleaching, but there are other corals that are bleaching aren't directly in the flow of where I poured the Alk additive. The last week I've been diluting the Alk and ca in RO/DI before adding to the return overflow in the back of the nano but the bleaching continues to worsen.

Any help is greatly appreciated. Photos attached.
Many thanks,
Chris

 

[mrturritos]

I'm no sps expert but I'v had one alk drop from 10 to 7/ calc from 440 to 360 and just about all the sps lost significant color. I can only imagine several swings will cause them to recede. I started dosing and keeping stable numbers and things are already doing better.

Maybe consider reducing the amount of sps in the tank to lower the uptake of alk/calc? That or testing 2-3 times a week (reliable kits a must!) until you dial in how much to dose without having such large swings.

 

[cmiller]

Thanks for your reply. Yeah, it's been a struggle to dial in the proper amount of additives to hit it right. Ever heard of Alk bleaching corals if it is added directly into the tank and it hits the sps before dissipating?

 

[mrturritos]

As long as you are dosing it in a high flow area like in front of a pump it shouldn't be a problem. If you are pouring it into the stream of the mp-10 turn it up to the max while you dose and ramp it back down once all of it dissolves. Again no authority in sps but my guess would be the big swings you're experiencing are causing the problems; if you have good enough flow that they grew into small colonies I really don't think alk being dosing in a tank is any bit of an issue.

I put the wp-25 in my tank on max power then pour the liquid alk into the tank, nothing closes up (sps or lps) as a result of the alk flying around and then dissolving shortly after. After a 20-30 seconds I put it back onto the random mode and things go back to normal.

 

[kevinpo]

Hello,
Sudden swings in alkalinity often cause bleaching in Acropora corals.

Regards,
Kevin

 

[cmiller]

Thanks for the comments/advice folks. Actually, After a closer look at my parameters log book looks like Alk 'only' fluctuated betw/ 8-11 for about 4 weeks. still that may be enough to cause the bleaching I suppose. I've had Alk stable at 9 for the last week and ca stable at 390, but the sps look like they're still bleaching. Any thoughts on how long till bleaching stop and I start seeing the sps recover and start seeing growth with the levels stable?

 

[mrturritos]

it takes several weeks for most sps to gain color back.

 

[NW Fish Dude]

Did your sps stop bleaching? Curious as to how they look a month or so later now. I am having similar issues, and can't figure out if it's low/fluctuating alk, or too much light from the LED's.

 

[itche_scratche]

Need to stable alk

 

[NW Fish Dude]

Yea, I agree. Just hooked up a couple of dosing pumps. Hopefully 2 part maintenance dosing will help me avoid alk drops and keep things much more stable.

 

[cmiller]

Yea, I agree. Just hooked up a couple of dosing pumps. Hopefully 2 part maintenance dosing will help me avoid alk drops and keep things much more stable.

Yup, seemd that a combination of Alk and ca swings and 2-3 degree temp swings caused the bleaching. Bleaching has stopped and the tank is stable and growth has returned. I wasn't accounting for the size and growth of sps after several months of them going off like gangbusters. I need to dose 25ml of Alk and ca 2x/day to keep Alk at 10 and ca at 400.

Fish dude, I'm Interested in knowing more about the dosing pump you set up?

 

[NW Fish Dude]

I bought a couple of John Len liquid dosing pumps, and they each draw separately from my alkalinity and calcium solutions, and drip into my sump. I have one to dose in the morning, and one at night, so they don't mix. Each drips in over about a 45 min period of time. Runs at just over 1 ml/min.

 

[NanaReefer]

Inna tank that size it may be easier to keep parameters stable via more frequent water changes..less invasive also.

 

[NW Fish Dude]

Good point. Though depends a bit on your salt mix. I have a 140 g total system. Works well for me.


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[NanaReefer]

Good point. Though depends a bit on your salt mix. I have a 140 g total system. Works well for me.


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The OP has a 28g, much easier to do WC's

 

[NW Fish Dude]

Yes. I tried a nano a while back. I found it much harder to keep my chemistry stable than with a bigger system.

 

[NW Fish Dude]

Yes. I tried a nano a while back. I found it much harder to keep my chemistry stable than with a bigger system.