should i invest in a strontium test kit?


New member
hi all,

im looking for a little advise. maybe im missing something.

ive been fighting a losing battle so far in my 28g nano tank. i have about 10 various sps corals that are receding at the base and nothing i have done so far has helped. i will go over water parameters.

alk- 7.5-8 dkh
phos- .03 down from .06 over last 2 weeks.

i have 2-vortech mp10's in nsp mode. i was set at about 60% and i turned them up to 100% last week. maybe was lack of flow

i lowered alk from 8.5 to 7.8 over a 2 week period.

i raised the temp from 75 to 77 average.

here is some other equitpment running on my tank.

calcium reactor. ph 7.0 60 drips per min.

bio-pellet reactor with 100 ml of pellets flow at 250gph. ( only been running for 3 weeks) i am tring bio-pellets to see if they will help with stn problem.

phos ban reactor with rowaphos.

aqua-c hob skimmer.

lighting - 150w radium 20k bulb hqi ballast run for 7 hours, 2-18w actinics run for 12 hours. 5" from water surface.

i think all of water parameters are in line. the only thing i dont test for is strontium and iodine. im wondering if low strontium could be causing problems. but ive heard with a calcium reactor normally levels will be ok.

two other things a can thing of that could cause the stn issue.

i have 2 leather corals in the tank. could that cause problems?
was my phosphate to high at .06? had a small hair algea problem.

i only do 10% water changes once a month but i dose trace elements once a week.

i was feeding corals zooplankton and amino acids 2 times a week but stopped that until i can lower my phosphate. i dont think its lack of nutrients.

sorry for long post im just a little frustrated. any advise will help.

Randy Holmes-Farley

Reef Chemist
Premium Member
IMO, strontium is unimportant and I wouldn't bother measuring or supplementing it.

I'd stop the trace elements. You certainly aren't loosing corals due to lack of trace elements. And maybe some are too high.

Do you use any GAC? The leathers may be irritating the SPS.

Yes, 0.06 ppm phosphate may be too high for some SPS.


New member
thanks randy.

ive been using chemipure elite and purgien combined. should i discountinue them and use gac instead?

im lowering the phosphates slowly. my goal is .01 .

i will stop trace elements and plankton feeding for now.

do u think i should lower/raise my alk some?

i am in the process of coverting my 125g to salt. i will move all the softies over to there.

anything, that u can think of that im doing wrong?

i was also considering changing the 20k radium bulb to a 14k pheonix. even though i like the look of the radium i was thinking it may help with growth.
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Randy Holmes-Farley

Reef Chemist
Premium Member
The chemipure and purigen maybe adequate if you replace it often enough (maybe every 3 weeks). :)

I do not think the alk is an issue.

I don't se eany other issues. It unfortunately can be very hard to track down the answers to such problems.


New member
if i have to replace it that often i might as well just use gac in a media bag and place it in the sump.

ill will just keep trying to reduce nutrients for now.

what are your thoughts on switching from radium to pheonix? ive read the par values are close. pheonix is just a little whiter.


Premium Member
The Chemi-Pure Elite has some GFO in it, if I remember correctly. You might want to add some more Rowa-Phos, if the Chemi-Pure is added a significant proportion of the phosphate adsorbption.


New member
there are a lot of links between carbon dosing and stn issues. Also there are a lot of things changing in your tank. How long do you wait to check to see if something is working? Let things settle down and try changing one thing at a time. I have the 14k ph and its a great bulb, but with all the other changes it would not be a good time to change lighting as well. One consideration might be to investigate the use of AA. Some also contribute as a carbon source, and a hob skimmer might not be enough for the pellets your running. "I would stop the trace elements, and do whater changes to clear anything out" let things stabilize and see where your at.


New member
I will most likely add some more gfo and do a small water change. I still think most of my problems are phosphate related. What is aa?
Dosing amino acids is touchy. Too much can cause tissue necrosis in coral. If you are having problems with your coral, I would stop dosing the amino acids and anything else except maintaining alk, calcium and mag. You should reduce phosphate and nitrate to appropriate levels. Increasing lighting suddenly can cause tissue necrosis in coral as well.

Also red bugs and disease can cause tissue necrosis at the base.
If there is extensive damage to your coral, I would frag out the damaged areas well beyond the noticeable damage. Once coral suffer tissue necrosis they are subject to disease invasion and the longer you let it go the more likely this will occur.


New member
I will stop dosing everything. I'm going take a few of the corals out, frag them and give them a revive dip. Maybe that will help.


New member
Yeah I would stop dosing everything. No need for anything but ca and alk maybe mag if your tank needs it. 2 MP10s in a 28g nano that is way much. Run only one at around 70-80% on Reef Crest that will be perfect. 2 at 100% in a tank that small you will blow the tissue off your corals, over 100X turn over. What lighting are you running and what skimmer? In smaller nano cube a good skimmer and regular water changes should be enough to keep water clear and clean and there should be no need for all the carbon, puregen ect.


New member
I'm using a aqua c remora skimmer and a 150w radium mh. I lowered the mp10 to about 80%. I also have a 15g sump.


New member
did a 4 gal water change last night. i tested the alk of i/o salt mix and it was about 10.5 dkh. the alk in my tank was at about 7.4 yesterday. what alk should i shoot for?

ive heard running pellets u need a lower alk. but ive noticed with the lower alk ive been getting much less coral growth. should i shoot for 9 ish?

Randy Holmes-Farley

Reef Chemist
Premium Member
7.4 dKH is fine. Most folks, except perhaps ULNS systems with SPS and especially thos eusing zeovit, seem to do well in the 7-11 dKH range. The latter ones seem to have issues above 8 dKh or so.


ReefKeeping Mag staff
Premium Member
I'd stop the trace dosing and wouldn't use any strontium or iodine.

There are no clues I can pick up on in the parameters ,perhaps alk fluctuations combined with PO4 but there really aren't high variations noted. No sg was listed , I assume it's ok. FWIW, though I grow many varieties of sps and have not seen any stn issues when PO4 was at or slightly over .06ppm.Flow seems ok and should help offset any nightime hypoxia. Organics from the pellets could have contributed to the stn; In any case,I don't see how they could help if nitrate is at 2ppm without them.
Perhaps, a predator, fish, redbugs or acro eating flatworms.
I personally don't have trouble with leathers and sps but Allelopathy could be an issue.


New member
my sg stays between 1.025-.026 all the time. my alk never swings more then .5 dkh over a few day period, maybe less then .5 .

i havent noticed redbugs or worms but i see my hermits crabs picking at them every now and then.