At what rate can I safely lower salinity.

Cunning_plan

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In Short:
I have salinity at 45+ ppt. How can quickly can I take it down to 35? Should I be water changing with RODI water or low salinity water.

In Long:
I have been running a reef tank for around 5 months now. It's a reefer 250 (55g). Over time I have gradually tried to add corals. With a few minimal exception these have all died. As it stands living I have 2 GSP frags, a kenya tree frag, and 5-6 very closed up zoas. I also have a couple of cleaner shrimp, a convict Blenny, 2 small clowns, a lemon damsel and a firefish.

Over the past 3 months I have tried adding corals 4-5 times. In some cases they have done fairly well, I had a hammer and an elegance coral that seemed to be thriving for a while. In others though, they just died. The few SPS frags I tried to add died within 12 hours. No zoa has ever opened more than 1/3 of the way. In response to this, I tinkered far more than I should have. In terms of flow, placement, lighting and nitrate/phosphate removal. I always assumed it was my basic chemistry but on multiple test kits showed 0 Amonia/Nitrite and close to zero Nitrate/Phosphate. Salinity always showed around 33.

Given my salinity had always been a touch low, I decided that could be my cause. Over the course of 2 weekly water changes I raised it from 33-35. At that point what few corals had been prospering died.

At that point I almost completley gave up. I was on the verge of just keeping fish. But I read online about people with the same refractometer as I have having to calibrate it frequently. Having never done this I decided to give it a go. I bought a 35 ppt test solution and put it into my refractometer. It came out as 20. Assuming I had a bad batch, I ordered a second sample from a different brand. 20. Reading online I saw that a lot of people simply calibrate to RODI water. I tried that. -15. It was so out, the calibration dial wouldnt even let me correct for it.

So here I am. I've ordered a new refractometer which should come tommorow. But I need to work out what to do. My salinity is currently running somewhere in the 45-50 range. What are my next steps?

As a small aside, I realise that I have made almost every clasical rookie mistake possible here short of adding 3-4 tangs to my tank. My aim once this is sorted out is just to run the whole thing stable for a month or so before doing anything else.
 

Randy Holmes-Farley

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I would be very careful to not assume it really is 45-50 ppt.

What brand fluid did you use?

What brand refractometer?

If you calibrate with RO/DI, what does the tank water read? Is that where the 45-50 comes from, or did you try to add the 35 to -15 to get it?
 
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Cunning_plan

Cunning_plan

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Thanks for the response.
  • My refractometer is from red sea
  • The calibration fluid was made by a company called Sailfert. The second came from a company called Faremax. Both were labelled as for refractometers not, for the electrode kind
  • I cannot move the calibration on the refractometer far enough such that RODI comes to 0 or the calibration comes to 35. At absolute best I can get it to within 5-10.
  • My 45-50 is infrerence from the error. If the scale in non linear then I could be completley wrong
 

Rybren

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Do you know anyone who is into reefing? Perhaps you could get them to check a water sample for you. In addition, most LFS will check a sample.

If it were me, I'd confirm the salinity before taking any action.
 

Snoopy 67

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OK, now as far as salinity, you can drop salinity fast. When I did maintenance & had ick in the tank we went right down to 1.0010. Going UP has to be done SLOWLY.
 

Reef.

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OP in the meantime whilst you wait you could make a test sample of salt water up, I know for me 38 grams of salt added to a litre of water is near enough 35ppm.

but I think with all the tests you have done already your salinity it way too high.
 
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Cunning_plan

Cunning_plan

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OK, I borrowed a neighbors refractometer. Calibrated that against both RODI and my salinity test solution (both bang on).

My tank is at 50ppt.

I will validate again when my new one arrives tommorow but that's looking fairly certain now.
 

Reef.

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OK, I borrowed a neighbors refractometer. Calibrated that against both RODI and my salinity test solution (both bang on).

My tank is at 50ppt.

I will validate again when my new one arrives tommorow but that's looking fairly certain now.

Mate I think you can now safely say it’s high, if my tank I would take out the fish, acclimatise them into 35ppm water slowly, then correct the tank to 35ppm then acclimatise the fish back into the tank, I would feel a slow reduction of salinity of the tank water would just prolong the damage to the fish and corals.
 
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Cunning_plan

Cunning_plan

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Mate I think you can now safely say it’s high, if my tank I would take out the fish, acclimatise them into 35ppm water slowly, then correct the tank to 35ppm then acclimatise the fish back into the tank, I would feel a slow reduction of salinity of the tank water would just prolong the damage to the fish and corals.

Thanks. Do you have a view on how long it would take to acclimatise them down that far? I hear about people taking weeks to do 2ppt and I'm looking at doing 15.
 

Reef.

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Thanks. Do you have a view on how long it would take to acclimatise them down that far? I hear about people taking weeks to do 2ppt and I'm looking at doing 15.

I would tag Randy, he is the guy to ask, but if my tank I would do the fish in a couple of hours but please get advice of others first.
 

Miller535

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If I plug your info into hamz reef, this is even what it says to do



FYI: You can find this calculator and many other helpful ones at :


hamz2.PNG
 
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