Water parameters after first water change

[Gruca]

So I just did my first water change after setting up the tank and letting it cycle. Using Tropic Marin Pro Reef salt. I mixed 35g of saltwater at 1.023 salinity. Before the water change my alk was 9.5, calcium was around 400 and magnesium was about 1150. I had been removing saltwater and replacing with freshwater to get the salinity down after adding rocks and that’s where the parameters ended up.

Today I did the water change and my parameters went down to 8.09, calcium to 377, and magnesium to 1078. I’m confused as to why adding saltwater decreased these so much.

 

[p1u5h13r4m24]

However I didn’t see your thread until after. And it would make sense to use a calibration solution closer to where you are testing. So I stand corrected

 

[Randy Holmes-Farley Verified Community Expert]

Hey! This is directly from the Red Sea refractometer calibration instructions
Calibration:


Alignment should always be carried out with the


instrument at 22-25°C. Allow the refractometer to stand at


this temperature for 30 minutes before alignment.


1. Remove the cover from the alignment screw.


2. Place a sample of DI water on the glass prism and check


the salinity reading as directed above.


3. If the reading is not exactly on the zero ppt mark on the


scale, adjust the position of the reading by rotating the


alignment screw with the screwdriver provided until the


reading is zero ppt.


4. Replace the cover from the alignment screw.

The Red Sea is designed as a seawater refractometer, but using an accurate standard is always correct and eliminates manufacturing error concern. The temperature directions are not correct in that any temperature within the ATC range is fine for calibration.

 

[Gruca]

For the record, I’m stupid and forgot to calibrate it…please judge harshly.

 

[Badger_Reefer]

For the record, I’m stupid and forgot to calibrate it…please judge harshly.

Calibrate it to 1.025 sg or 35 ppt … at 25 celsius for 30 seconds. Then clear the prism glass and add aquarium water’s droplet and check the salinity reading

 

[Randy Holmes-Farley Verified Community Expert]

Calibrate it to 1.025 sg or 35 ppt … at 25 celsius for 30 seconds. Then clear the prism glass and add aquarium water’s droplet and check the salinity reading

FWIW, the sg of 35 ppt seawater is about 1.0264. :)

 

[Gruca]

I did the calibration using the 35 ppt solution. Tested my tank’s water and it’s 1.025.

 

[Randy Holmes-Farley Verified Community Expert]

I did the calibration using the 35 ppt solution. Tested my tank’s water and it’s 1.025.

That’s a fine value.

 

[56longroof]

Just my 2 cents but throw the refractometer in the trash and get a Tropic Marin hydrometer. No calibration needed and it's probably one of the most accurate.

 

[Randy Holmes-Farley Verified Community Expert]

Just my 2 cents but throw the refractometer in the trash and get a Tropic Marin hydrometer. No calibration needed and it's probably one of the most accurate.

It’s not very useful for, say, figuring out what salinity a new creature in a bag is currently exposed to. :)

 

[Reef.]

Your post is not very clear…Tropic Marin Pro salt is not 9.5alk (if the alk reading is correct) so if I have understood your post correctly even before adding the rocks your salinity was high.

This definitely sounds as if its a salinity issue.

Buy a Tropic Marin hydrometer, they don’t need calibration and are alot harder to use incorrectly whereas your refractometer is extremely easy to use incorrectly even if it’s calibrated correctly.

 

[56longroof]

It’s not very useful for, say, figuring out what salinity a new creature in a bag is currently exposed to. :)

No it is not. But I acclimate everything per the vendors instructions.

 

[Reef.]

It’s not very useful for, say, figuring out what salinity a new creature in a bag is currently exposed to. :)

I’ve never received a fish or cuc with less than 500ml of water in the bag and corals I don’t even bother acclimating so the salinity for coral is irrelevant.

 

[Randy Holmes-Farley Verified Community Expert]

I’ve never received a fish or cuc with less than 500ml of water in the bag and corals I don’t even bother acclimating so the salinity for coral is irrelevant.

Ok, but many people do. I do.

 

[56longroof]

Ok, but many people do. I do.

Genuinely curious as to why? If your going to acclimate the new critters is it that important?

 

[Randy Holmes-Farley Verified Community Expert]

Genuinely curious as to why? If your going to acclimate the new critters is it that important?

Not sure how you acclimate, but my method involves knowing the salinity of the tank and the incoming water.

I prepare some tank water at the bag temp and salinity. Then immediately remove the fish from the bag and into the clean water.

That way, there is no risk from ammonia in the bag water becoming more toxic as the pH rises.

Then I can adjust the temp up to match the tank at any rate I want.

 

[56longroof]

Not sure how you acclimate, but my method involves knowing the salinity of the tank and the incoming water.

I prepare some tank water at the bag temp and salinity. Then immediately remove the fish from the bag and into the clean water.

That way, there is no risk from ammonia in the bag water becoming more toxic as the pH rises.

Then I can adjust the temp up to match the tank at any rate I want.

I only acclimate fish. Inverts and corals i just float to warm to tank temp. For fish I primarily only buy from Dr Reefs so I use their method.

 

[Randy Holmes-Farley Verified Community Expert]

I only acclimate fish. Inverts and corals i just float to warm to tank temp. For fish I primarily only buy from Dr Reefs so I use their method.

I don’t know what heir method is.