Sps issues

[kwmcdani]

Red Sea 525+ – SPS bleaching / LPS decline despite seemingly reasonable parameters – looking for ideas

I’m looking for some outside input on a mixed reef that has been giving me problems since transferring everything from my previous tank.

My previous tank was doing very well with SPS, LPS, mushrooms/softies and anemones. It developed a leak around Christmas 2025, so everything was transferred into my current Red Sea 525+. The old tank was much simpler (no sump) and was running around 160 PAR in the SPS area.

Current equipment

* Red Sea 525+
* 2x Red Sea ReefLED 90 G1, approximately 9” above tank
* Current lighting: Blue 100%, White 30%, Moon 0%
* MP40: Low Reef Crest, approximately 3,118–3,290 GPH
* ReefWave 45: Random/Forward at 70%
* Vectra L2 return: currently 82W
* Aqua UV 15W running 24/7 on a dedicated ~210 GPH pump
* Skimmer
* Large chaeto refugium
* Filter sock
* Poly-Filter currently running

The refugium light had previously been running 24 hours/day. On Sept. 17 I changed it to 12 hours/day on a reverse light cycle because I was concerned I might be exporting nutrients too aggressively.

Current measured water parameters – Sept. 21

* Alkalinity: 8.5 dKH – Hanna
* Nitrate: 10.6 ppm – Hanna Marine Master HR
* Phosphate: 0.02 ppm – Hanna Marine Master
* Calcium: 509 ppm – Hanna (planning to repeat because previous measurement was considerably lower)
* Magnesium: not retested yet
* Temperature: approximately 78–79°F
* Salinity has been independently checked with both my equipment and at the LFS and has been consistent.
* LFS has repeatedly tested the water and says everything looks good, including no detectable copper.

Recent trends

Alk:
8.7 (9/7) → 8.7 (9/8) → 8.5 (9/21)

PO4:
0.03 (9/8) → 0.03 (9/16) → 0.02 (9/21)

Calcium:
435 (9/8) → 509 (9/21) — repeating this test.

Magnesium was 1540 ppm on 9/8, so that is also being repeated.

PAR

One fish-store SPS test coral has been kept at approximately 110 PAR.

A chalice is around 106 PAR.

Maximum PAR I’ve measured in the current tank is roughly 230.

I also recently obtained several SPS frags from another reefer. I personally measured his tank and most of those SPS were receiving 500–600 PAR, with some areas over 700 PAR. All of the frags I received came from near the top of his tank. Therefore even the highest locations in my tank are a major reduction in PAR compared with their previous environment.

What has been happening

Earlier in this tank’s life, I lost multiple SPS rapidly. Some would bleach/lose tissue within roughly a week. Torches/Euphyllia became progressively smaller, anemones nearly disappeared, while mushrooms and fish generally did considerably better.

One potentially important detail: early after transferring into this tank, the ReefLEDs were running 100% white for a period. That has since been reduced substantially.

Flow was also previously considerably higher. MP40 was around 3,744 GPH, ReefWave was 80%, and the Vectra was at 102W. I’ve since reduced all three. Some soft corals appeared to respond positively to the flow reduction.

Recently things seemed to stabilize. The inexpensive fish-store SPS at ~110 PAR survived much longer than previous SPS, and the newer donor SPS initially retained tissue.

Now I’m seeing SPS paling again.

The fish-store SPS that had been stable at ~110 PAR is developing pale/bleached-looking areas. One of the donor SPS is also becoming very pale/white at the upper tips. I’m trying to determine whether this is actual tissue loss versus severe bleaching, but the change is noticeable.

This is particularly confusing because the donor SPS came from 500–600+ PAR, while the fish-store coral is only receiving ~110 PAR. That makes simple excessive PAR seem less obvious as the common denominator.

At the same time, established LPS still aren’t showing the recovery I’d like, although recently added soft corals are opening/expanding.

Other troubleshooting already done

I discovered that filter socks had previously been washed in our household washing machine (with bleach cycles but the machine normally handles detergent), so I stopped using those because of the possibility of detergent/surfactant contamination.

I’m currently running Poly-Filter and UV. Water clarity improved dramatically after getting the UV operating properly, and visible cyano has disappeared.

I have considered sending an ICP test because I’m wondering if there is something we’re simply not measuring.

I also have an Orphek OR4 iCon UV/Violet bar on the way, but I do not plan to increase lighting aggressively while this is happening. I’ll PAR-map the tank before and after installation.

What I’m trying to figure out

With alk at 8.5, nitrate 10.6, PO4 0.02, stable temperature/salinity, relatively modest PAR, and SPS from very different previous lighting environments both beginning to pale, what would you investigate next?

I’m particularly interested in opinions on:

* PO4 being only 0.02 despite NO3 being 10.6
* possible trace-metal/contamination issue and whether ICP is warranted
* whether the high Ca/Mg readings could be relevant if confirmed
* whether the current flow could still be excessive
* anything else that could explain SPS + LPS problems while fish and mushrooms generally do well

I’m trying not to shotgun changes at the tank. I’d rather identify the most likely issue and change one variable at a time.

I think that’s enough detail that the experienced Reef2Reef people can actually troubleshoot it rather than giving you the usual “check your parameters” response. It also includes the odd part of this case: NO₃ is actually 10.6, so we’re not dealing with a generally nutrient-starved tank, but PO₄ is sitting very close to the floor at 0.02.

 

[Mr. Mojo Rising]

All that text is helpful but pictures would really help too. I got a bit lost in the text, but it looks like your sps are in 110 par? Even 230 par is pretty low for sps corals, I would suggest 350+. But LFS often have lower par, because it takes a long time to see the affects of low lighting compared to high lighting which can damage a coral almost immediately. IMO knowing the LFS par is helpful to give you an idea of how to acclimate the corals but your not supposed to keep them in that par level forever, your supposed to acclimate it to the correct par level.

 

[kwmcdani]

So I have moved SPS the one LFS sps up to higher PAR. The other SPS are at the 230+ range. I have ordered a Orphek LED Bar to supplement my current lights. I will add several pictures below.

 

[ChrisfromBrick]

yea you will see a difference with high par I think. Your ALK looks fine. Just go slow with raising the lighting.

Yes- get an ICP. I just did ATI. Takes about a week to get results, sometimes 2 weeks. It was $70

 

[jackson6745]

An ICP is always warranted. Good to see all of your markers besides checking for toxicity. Keep in mind it must be an MS-ICP. You wont get a detectable level of many potentially toxic trace minors with oes tests.

You need to upgrade lighting or stick with low light Sps such as anacropora, Monti, maybe some Valida etc. I didn’t see the age of your system and rock used etc. A mature system and biome can make or break the systems ability to keep acros alive.

Detailed photos will show more than you can type.

 

[Naturalreef]

I noticed the high Pur that the reefled put out would bleach sps pretty quickly at your intensity with that low of a po4 reading. Reefled numbers are misleading when using a standard par meter that misses a good portion of the Pur. I probably missed it, but how high are your sps relative to the light?

 

[ReneReef]

Its very simple.
Two Reef LED 90 on a 450 Liter tank is waaaay too little.

Double that and run all blue and white channels at 100% for at least six hours a day.

 

[Krux]

I suspect heavy metal poisoning

 

[kwmcdani]

I suspect heavy metal poisoning

I ran a Poly-Bio-Marine Poly-Filter pad and it didnt show anything. As I was worried about something in my rock.

 

[kwmcdani]

Its very simple.
Two Reef LED 90 on a 450 Liter tank is waaaay too little.

Double that and run all blue and white channels at 100% for at least six hours a day.

I ordered a 60" one of these to supplement the reef LED's for now. Its not here yet

https://shop.orphek.com/collections...ucts/or4-icon-uv-violet-reef-aquarium-led-bar

 

[kwmcdani]

 

[kwmcdani]

Before my current Red Sea 525+, I had a JBJ 65-gallon aquarium that was doing extremely well as a mixed reef. I had healthy SPS, LPS/Euphyllia, anemones, mushrooms/soft corals and fish. The SPS were actively growing, and I was not experiencing the repeated bleaching and tissue-loss problems I'm dealing with now.

The JBJ 65 was a much simpler system than my current tank. It did not have the large sump/refugium and nutrient-export setup that I have now, and circulation was provided by internal pumps.

For lighting, I was using NICREW HyperReef 200 rather than Red Sea ReefLEDs. It was the single overhead fixture with three circular LED clusters that can be seen in my old tank photos.

That tank was thriving until Christmas morning 2025, when the aquarium developed a leak. The livestock had to be moved, and I ultimately transitioned everything into my current Red Sea 525+.

The new system is substantially different. I'm now running a sump, skimmer, filter sock, large chaeto refugium, UV sterilizer, controllable return pump, MP40 and ReefWave. Lighting also changed completely from the single three-cluster LED fixture to two Red Sea ReefLED 90 G1 fixtures.

After moving into the 525+, coral health progressively changed. I began experiencing repeated SPS bleaching/tissue loss. Some newly introduced SPS would deteriorate within roughly a week. My torches/Euphyllia became smaller, the anemones declined severely, and other corals struggled. Fish continued doing well, while mushrooms generally tolerated the system better.

One potentially important event after the move was that the ReefLEDs were running with the white channels at 100% for a period while the corals were in the tank. We've since reduced the lighting considerably and measured PAR throughout portions of the aquarium.

The reason I'm looking for a broader explanation than simply "not enough light" is that the old JBJ 65 successfully grew SPS and maintained a healthy mixed reef, while the substantially more sophisticated Red Sea system has struggled with multiple types of coral and anemones.

A lot changed at the same time: tank, lighting technology and spectrum, flow, sump, mechanical filtration, skimming and refugium/nutrient export. I'm trying to determine which of those changes—or combination of changes—is responsible rather than continuing to make random adjustments.