Calling All SPS Experts

Spartanman22

Spartanman22

Well-known member
Alright I'm at my wits end with this one. I have some SPS that have been STNing lately, and others that are showing good growth. I have been testing almost daily to determine if my parameters were shifting and the most recent results were as follows:

Ca: 440 (salifert)
Mg: 1300
Alk: 7.9 (salifert)
pH: 8.3 (probe)
Salinity: 1.027 (very consistent)
Temp: 78.0
PO4: Undetectable (salifert)
NO3: <1 (salifert)

I have had some small temp swings lately (2 degrees at most). For some reason my heaters aren't working through my RKE. I'm looking into a mew heater currently. But in my experience 2 degree temperature swings aren't the worst thing.

What's confusing me is if it were a parameter issue such as Ca, Alk, pH I would expect to see fairly uniform response amongst all my SPS not just a handful. I have not changed anything other than water changes and monthly carbon/GFO replacement. RODI effluent tds is 0 (filters were replaces about 4 months ago).

My system is a 25 gallon display, 20L sump (~12 gallons), and a 12 gallon frag tank. There are currently 6 fish in the tank. DT lighting is am OR-T247 and frag tank lighting is a Kessil a350. Flow is a MP10WES and skimmer is a SCA 303.

My latest hypothesis is lack of nutrients. I have not been able to detect and PO4 or NO3 for quite some time, despite 3-4 feedings a day of dry and a homemade frozen blend. I have recently shut off my gfo and carbon reactor and begun dosing acropower to see if I can increase nutrient levels. I have found that the STNing is slightly less prominent in the frag tank and I believe this to be because of a much reduced flow through the frag tank, therefore nutrients are maintained longer.

Does it sound like an issue of a poorly managed ULNS system or is there something I may be missing? Any and all suggestions are welcome!
 
I forgot to mention that all pieces STNing are still showing good growth vertically. They are just STNing from the base up.
 
Undetectable po4 is a good place to start imo. That's to clean his often and what do u feed the tank
 
R u sure only 2 degree i had this happen and during day temp swing 2 degrre but night temp dropped 7 degree lost two colonies rest recovered once i figired it out.
 
+1 to madjoe. Your tank is too small and easily swings. Get a better heater :)


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Try dropping your alk to 6.5 - 7 and keep it there for a few weeks and see if it stops.

Very long story short, very similar if not identical problem with the same parameters both ended up being traced back to alk being at 8-8.5. Only after having it happen twice did I make the connection. Keeping it at 7.5 and below stop the base up STN on the few pieces. Just like yours others thrived when some STN'd.

The issue is many low nutrient systems can't handle higher alk. Either tip burning or base up STN start.
 
jrpark22000 said:
Try dropping your alk to 6.5 - 7 and keep it there for a few weeks and see if it stops.

Very long story short, very similar if not identical problem with the same parameters both ended up being traced back to alk being at 8-8.5. Only after having it happen twice did I make the connection. Keeping it at 7.5 and below stop the base up STN on the few pieces. Just like yours others thrived when some STN'd.

The issue is many low nutrient systems can't handle higher alk. Either tip burning or base up STN start.
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Very good thought...
 
I agree with jrpark22000, im actually now recovering from RTN my self....my problem was high alk (12) my tank is used to 7 ....i have no idea what caused my spike...but it took about a week or two for it to drop back to 7 on its own...all my sps came SUPER close to a whipe out...
 
I've also experienced two cases of RTN on two different SPS. In the first case of RTN, my alk was about 11. I've since brought it down to 8.7 but I still got RTN on another SPS yesterday. All other params with the exception of phosphate are fairly stable. Phosphate has been fluxing between .04 and .09. I know I've only lost two pieces which is nothing comparing to other people, but the fact that I don't know why is very frustrating.
 
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madjoe said:
R u sure only 2 degree i had this happen and during day temp swing 2 degrre but night temp dropped 7 degree lost two colonies rest recovered once i figired it out.
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I am quite certain my tank temp has not dropped below 76.5 since I have a safety net heater programmed which has been keeping the temp up when the other one doesn't want to kick on.

Some of my pieces are paling which is why I initially decided to start dosing AA's. I ve been going about a week now. Haven't seen much improvement as far as color yet, but PE seems to have improved slightly.

It appears I have two options: leave alk alone and attempt to increase nutrients by shutting of gfo and carbon reactors, feeding more, possibly increasing my bioload. Or leave nutrients alone and lower alk to 7.0.

I initially was leaning towards adjusting nutrients because tinkering with alk makes me nervous, but I've tried increasing nutrients in the not so distant past with no luck. I have four fish arriving at the end of this week and I'm hoping this will help to increase my PO4 and NO3 to detectable ranges.

I plan to begin today by decreasing the time my alk pump is on by 3 seconds a day (this should equate to a couple of drops) until I have hit 7.0-7.5.

Thanks for all of the suggestions everyone! I have never maintained alk this low, but then again I have never had this much of an issue keeping nutrients around (whoever said overstocking was a bad idea ). I've been reefing for almost 9 years and this just goes to show nobody knows it all! Thanks for filling in for my lack of understanding!
 
Shut your reactors down. Just have carbon bag in sump. If you are using ROX carbon or something similar, it can cause RTN if used in a reactor because it totally strips the water of everything.


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I have actually had some cyano show up on the sand bed.

So you'd suggest shut down carbon and gfo reactors and adjust alk to 7.0?
 
Spartanman22 said:
I have actually had some cyano show up on the sand bed.

So you'd suggest shut down carbon and gfo reactors and adjust alk to 7.0?
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Yes. Change 1 thing at a time. Don't shock corals more by changing too many things at the same time.


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Ok sorry for the confusion but either turn off reactors OR adjust alk but not both? I was planning on just adjusting alk and leaving the reactors running.

Tank could you please explain your cyano question. Is that an indication of a potential issue?
 
When problem shows up and u know ur levels r all in line . Only one solution ,do 5 to 10% WC every 3 days. Works all the time for me instead of adjusting this and that.
 
I've done about 4 5 gallon water changes over the past 2 weeks. It seems to have helped a bit, but if it is a nutrient issue water changes won't help solve the underlying problem
 
Spartanman22 said:
I have actually had some cyano show up on the sand bed.

So you'd suggest shut down carbon and gfo reactors and adjust alk to 7.0?
Click to expand...

If Cayno Bacteria is present this can be a problem in a small system like this. It's bacteria that needs to be removed manually once it's in the water column it can cause all types of problems. There is little info on Cyano Bacteria if it kills coral without smothering the coral but it's Bacteria just like an infection if it's present it can harm your corals and some Cyano Bacteria can be dangerous to corals health. 1st don't blow it off cause it's Bacteria it needs to be removed manually just like Bubble Algea once popped the spores will go everywhere and create more Bubble algea. Same with Cyano if you blow it off where is the algae and bacteria suppose to go? It will just spread to other parts of the tank and sump. IMO I will try to work on removing the Cyano Bacteria. More and more I read someone with an STN problem Cyano Bacteria has been present in the tank. Not just here but many other forums also
 
stop your reactors first. My alk changes from 7-9 depending on the week, usually around 8 and my tank is also low nutrients due to carbon dosing and giant skimmer and I don't have RTN issues, usually sometimes get pale corals if I don't feed enough. my problems in past happened when I used Rox carbon in a reactor and totally stripped water of everything. Rox should only be used in a bag in sump unless you have heavy nutrients/crap in your tank.
 
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