Water params low

[DI68]

Hi I did a 80L water change on 300 L tank a couple of days ago as my Duncan's are dying and the alk then was a low 5 dKH and calcium 360. I tested it today and the alk is still the same but the calcium has dropped to 300? Nitrates are 0 , PH 7.8. My tank has always maintained at 360 calcium, PH 7.8 - 8, alk 10-11 dKH and phosphate 0-0.25. I admit I haven't tested since around Feb as everything was stable ( although difficult to get PH up). I added reef builder this morning so that addresses PH and alk. Can I add the calcium supplement later today as well and how often can I add these safely? I have Red Sea NO3/PO4 to reduce the phosphates and am reading up on the manual at the moment. Just to add, I have changed the LFS where I buy natural SW as the other shop caught fire. My params have gone down since- co incidence or not?

 

[jeffaquarius]

What salt mix do you use and what is your salinity? What test kit do you use?

 

[DI68]

I buy my SW and it's sitting at 1.030. I just came home and one of my banggai cardinals is dying. I use API Reef Master test kit

 

[DI68]

I bought my own RODI filtration system too after the shop caught fire as we have to drive too far otherwise and the guy charges 4x the amount. I wonder if there is something wrong with the set up of that and it's not filtering right?

 

[DI68]

I have just taken about 10litres out and replaced with RODI and will keep doing that until I get the SG down.

 

[jeffaquarius]

There seem to be a bunch of stuff you need to do to keep your parameter on track. Most people may not be aware that the saltwater you buy from LFS are just for start up. If you have a reef tank it is always best to have an ro/di. API test kit is not reliable. You need to get a Phosphate test kit that can read below 0.05 ppm. I recommend Salifert. A reading of 0.25 is too high and will hurt your corals. For now I would suggest to keep on doing large power changes until you are close to normal. Raise pH with water surface agitation by power head. Take the parameter readings of your new saltwater before changing so you have an idea where it is at in the first place (calcium, dKH and magnesium). You can not dose calcium if magnesium is below 1300. Otherwise, precipitation will occur.

 

[DI68]

Thanks Jeff. I do have a RODI system but thought that was for top ups. I haven't heard anyone say that natural SW is only for set up? Thanks for the recommendation of Salifert. I had been looking at their magnesium and iodine tests through Reef online as I don't have these. I will look into phosphate tests too. I do have a phosban reactor but don't know how to connect it with this system.

 

[jeffaquarius]

The saltwater from LFS that you get with your 5 gal plastic container is prepared with synthetic salt mix. Unless you get them in boxes which have been processed. You can test parameter of salt water from LFS and usually the salinity is below for reef tanks.

 

[DI68]

The LFS has it's water delivered from a large company which sources the water from the ocean. I have looked into their website. I will be checking their params though next lot I buy.

 

[mrvincent]

1.030SG seems a bit high IMO... To know if your RODI work well, you can buy cheap TDS meter on ebay/amazon for 10-15$ as I did.

For sure 5dKH is low. I keep mine at 9.8.

If you dose something, do it SLOWLY, over weeks. Stability is the key. If you want to ajust salinity, don't drop it more than 0.001 per day or two.

 

[jeffaquarius]

The salinity of salt water from LFS can not be at 1.030. Assuming the OP hydrometer is accurate then the salinity has to be readjusted prior to pwc. Usually the LFS salt water is about 1.020 which is good for fish tank only.

 

[DI68]

What's a TDS meter?

 

[pauly79]

A meter that tests Total Dissolved Solids in your water sample.

Sent from my SCH-I545 using Aquarium Advice mobile app

 

[mrvincent]

With this you can see if your water is 99.9% pure. I'm reading 0ppm TDS in my RODI water, it means the water is so pure it does not conduct electricity.

And that's this level of purety you need in reef aquariums

I'll suggest you mix your own salt. I'm using RedSea salts, this is the best IMO, params are all high. Make sure you add salt to the clean water, and not the inverse.

If you have FOWLR tank, then go with cheaper salt like Fluval Sea Salts.

SG for:
1.020 = fish only
1.023 = LPS tank
1.025 = SPS tank.

Most hydrometers aren't accurate, so I keep mine at 1.023, but I know in real life it's 1.025, as somebody tested my water with a refractometer.

 

[jeffaquarius]

Refractometer can be accurate only if they are calibrated properly. I use 3 types so I have an idea if my refractometer is getting out of calibration. Water temperature can also affect the accuracy. You have to add or subtract if reading is not at 72F.

 

[DI68]

Sorry just saw the extra posts- this is a real science. The amount of learning can be overwhelming but thrilling too when all is running great...also.what's OP? I see people are referred to this and have never asked til now.

 

[jeffaquarius]

Original Poster of the thread which is you in this case.

 

[DI68]

Thanks Jeff