Help with unknown tank problem

[ratchp]

Hi. I have a mixed reef tank approx 300l including the sump. It has been setup and running successfully for 4 years. In the last 6 weeks all my zoa and torch coral have all closed up. I have a lot of pulsing xenia and other softies which are all looking healthy. My water parameters look ok, apart from a variance in Kh (between 7-10DKH). Calc is 450, Mag is 1250, Ph varies daily from 8.6 to 8.2, salinity 1.024, nitrates and phosphate is zero which I realise is too low. On the advice of my LFS I tried overfeeding to increase the nitrates and 'dirty the water' a little. I did this over a couple of weeks but all that happened was a big increase in red cyno and a green bubble algae. We then cleaned out the sump, and did a 50% water change (150L) but no difference. My torch corals are now dying and also my prize green anemone is very shrunk and on some days remains insides its 'ball' much to the consternation of the clowns who host it. The red cyno has also covered my SPS corals and i can no longer see the polyps after cleaning all the algae off. I do no know where to turn next. Please can someone offer some advice?? Thanks

 

[jmm]

Check your topoff water. If it's RODI discard and change filters. Start water changes with new RODI water. Just a guess, but it happened to me.

 

[tntdsol]

How often are you checking your DKH? To me a 7-10 swing is huge. Especially if it is within a couple days.

IMO many reefs have been successful with ULN as long as you keep the DKH stable and lower. If you were successful with low nutrients in the past then I would focus on keeping stable parameters.

What type of clean up crew do you have? Fish?

Does your Mag always stay in the 1200?

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[mcgyvr]

As stated that alkalinity swing is large...But you didnt define the time period in which it changes..

 

[ratchp]

The kH changes are over a week to 10 days. Maybe the issue is my RO water. I will try another 150litres of shop bought salt water and see what happens

 

[ratchp]

I only have 3 fish , 2 clowns and a scooter bleny the cleanup crew are 2 shrimps, 2 hermit crabs and a handful of turbo snails

 

[zachfishman]

Check your topoff water. If it's RODI discard and change filters. Start water changes with new RODI water. Just a guess, but it happened to me.

+1 I would be making my own RODI and not relying on LFS water to minimize variables. Any other equipment or regimen changes made around the time this started? A different/new dosing regime? Added a fuge made of non-acrylic plastic? Etc

 

[tntdsol]

I only have 3 fish , 2 clowns and a scooter bleny the cleanup crew are 2 shrimps, 2 hermit crabs and a handful of turbo snails

You said your tank was 300l? That is 80 gallons correct? I would recommend an increase in clean up crew. This would help solve the alge problem.

A 7-10 Alk swing over a week is a big one. This needs to be maintained at a constant level.

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[tntdsol]

The kH changes are over a week to 10 days. Maybe the issue is my RO water. I will try another 150litres of shop bought salt water and see what happens

I think the reason they were asking about RODI water is because a lot of contaminates can come from here. If you are buying from a LFS then they might not be as wifi efficient at ensuring 0 TDS as they should be. I know when I used to buy my water from a LFS every time I went in the salinity was different which caused salinity swings.

If it was me I would increase my clean up crew and then focus on maintaining stable water parameters.

I attached a picture of what you get in package deal from reef cleaners.

 

[peder]

Why do you start overfeeding When all was Looking good? Dont chase numbers!

 

[ratchp]

I was trying to raise the nitrates on advice of several fish shops.