Montipora coral sad

[Carp890]

100lt Nano tank.
Checked and double checked water parimiters, all good.
Tank is 3 years old regular maintenance 10%water change weekly. Vacuum sand etc
Put in a red plating montipora 2 years ago, looked great grew with plenty of colour, all other coral are great.
My red sea light started to play up???long story So l got a tesla light, seems very good. My montipora started to go down hill slowly. My light spectrum is 90% blue 10%white same as my old light. It looks like it has alge on it witch I brushed off
What can I do please.
There is a problem my nitrate is very high
75ppm hana check it drops to 60 after a water change 10 % which is normal but never stays there, I've done bigger changes 20% but it still ends up maxed out 75%.
Do you think this is the problem possibly if so how do I get nitrate down I've tried cutting down on the fish food. Would a big water change do it I don't want to crash my tank.
I don't have a detritus problem only clean the glass once a week

 

[Colin_T]

Do a massive (90-95%) water change using natural seawater or make up artificial seawater 24 hours before you use it and use reverse osmosis water to make it.

Change the light to white. The only reason you use blue light is to make corals luminesce or if you keep corals that come from deep water. Most corals come from shallow water and need red, blue, green, yellow and white light (the same as garden plants or aquarium plants).

 

[Carp890]

Will this not crash my tank? Pal

 

[MaloK]

Color ratio for a reef tank can vary depending on the specific corals. General guideline that works well for many reef setups as starting point.

White: 40-60%
Blue: 30-40%
Red: 10-20%
Green: 5-10%

You can do larger water changes to reduce nitrate, something like 33%-50%. Another cause for rising nitrate is insufficient biological filtration with a high bioload.

High nitrate levels can stress your Montipora and other corals long term. Adding a nutrient export system like a refugium or a chemical filter to help reduce nitrate levels could be a solution.

While it's not easy to add a refugium on a smaller tank it still doable.

 

[Donya]

+1 to large WC (as big as you can do w/o leaving the corals out of the water for more than a moment) with fresh mixed & heated water and also to chemical filtration to get those nitrates in check. 75ppm is kind of dire for a reef. Cut back feeding and look for detritus buildup; the cause of that nitrate needs to be sorted for a stony coral setup. Are you using a skimmer? Also is the new light same intensity/wattage or is it stronger? If stronger, you can “burn” corals by stepping up the intensity too fast.

 

[Donya]

Actually I think I see at least one component of the nitrate issue. I was on my phone earlier and I couldn't see the pics very well this morning as a result, but now I'm back on my PC. Am I counting 7 fish? That's a LOT for a 100L reef unless it's hooked up to a quite big sump. FOWLRs can play by different rules with that (to a degree - space issues still exist) since fish aren't as bothered by nitrate but reef nanos typically can't have more than 2-3 fish and keep nitrate down. Soft corals will be more ok with "dirty" tanks than stony corals. If you do have a skimmer (whether in-sump or otherwise) it should be producing quite a lot of sludge with that many fish; if it's not, then that could also be responsible for nitrates (and means time to tweak skimmer performance).

Looks like you also have some soft corals in there (couldn't tell before, sorry) - another possibility with the monty is that it's not actually the water or the light (although the high nitrates can't be helping even if they're not the root issue), but simply that all the corals have grown enough that they're starting to have turf wars. Or even that the new light prompted some spicier other corals to expand more and the extra reaching started some turf wars. Coral turf wars means some kind of chemical or stinging warfare, whether a direct bop from a tentacle with nematocysts or noxious compounds being put into the water or onto nearby surfaces. It shows up as tissue recession/necrosis on stony corals. Softies will often sulk first and then unceramoniously start melting when it gets too much. Some soft corals can be really bad for chemical warfare even if you run carbon, and by doing things like shedding slime coat it can slowly kill off stony corals that get hit. Toadstools, cabage, and some tree corals love to "snot" on nearby competitors. Hammers and torch also have long tentacles called sweepers that can go burn other corals up to quite a distance. In small systems, it's pretty common for a system to start out very diverse with lots of small frags that play nice together and then to have to prune it down to fewer species as things grow out more and start showing incompatibilities.