New to mixing salt water; question about alk matching

[Christopher Poore]

Hello all!

I am currently mixing 7gallons of water using Tropic Marin Pro. This is only my second time mixing salt water myself. My tank is currently at 8.6 ALK.

Last water change was 7gallons and the ALK was 8.5 before adding it to the tank

This time the water is showing up as 7.8 before adding to tank.

Why would this happen??
Should I raise the ALK in the mix before adding it to the tank to match my tanks ALK?

 

[lsaint88]

whats the temp of your water when you mix it?

 

[redfishbluefish]

What are you using to measure salinity? If it's a swing arm hydrometer, it's not very accurate.....and if your salt is off, so are your other numbers.

Also, what kit do you use to measure alkalinity?

 

[Christopher Poore]

whats the temp of your water when you mix it?

72deg at the moment. I should probably throw my heater in before adding it to the tank.

Would that effect the ALK level though?

What are you using to measure salinity? If it's a swing arm hydrometer, it's not very accurate.....and if your salt is off, so are your other numbers.

Also, what kit do you use to measure alkalinity?

I am using a refractometer. Any time I check salinity I use RO to 0 out the refractometer.

I am using Hanna to measure ALK

 

[Christopher Poore]

water is now 78deg.

 

[redfishbluefish]

Now measure salinity once you are at temperature. Also, you need to calibrate using calibration solution.....not RO/DI water.

 

[mcarroll]

Hello all!

I am currently mixing 7gallons of water using Tropic Marin Pro. This is only my second time mixing salt water myself. My tank is currently at 8.6 ALK.

Last water change was 7gallons and the ALK was 8.5 before adding it to the tank

This time the water is showing up as 7.8 before adding to tank.

Why would this happen??
Should I raise the ALK in the mix before adding it to the tank to match my tanks ALK?

What is the accuracy and precision of the test kit? Those results may be effectively the same.

 

[Christopher Poore]

What is the accuracy and precision of the test kit? Those results may be effectively the same.

I really like the Hanna test kit, I have tested using red sea and hate color matching/guessing. The Hanna ALK and Low Range Phosphate are both great tests, not too sure about their other products.

Now measure salinity once you are at temperature. Also, you need to calibrate using calibration solution.....not RO/DI water.

I will do so once I'm home. Assuming that Salinity is still the same @ 78degrees as it was @72degrees, what should I do?

Should I add my ALK mix to increase the ALK of the salt mix? I have not added it to the tank yet until I know exactly what I should be doing.

 

[Christopher Poore]

Should I be testing the big 3 on my salt mix EVERY time before adding?

If ALK / Mag / Calc are not equal to my tanks waters I should dose them to match?

Thoughts?

 

[mcarroll]

Hello all!

I am currently mixing 7gallons of water using Tropic Marin Pro. This is only my second time mixing salt water myself. My tank is currently at 8.6 ALK.

Last water change was 7gallons and the ALK was 8.5 before adding it to the tank

This time the water is showing up as 7.8 before adding to tank.

Why would this happen??
Should I raise the ALK in the mix before adding it to the tank to match my tanks ALK?

Salt mixes are rarely if ever 100% uniform after they are shipped to their final destination. This means that there will be some variability and parameters from mix to mix unless you are using one whole bag or box or bucket of salt per mix. This is the way you really should be doing it, but in practice it's rarely done because it's more expensive.

I can tell you I've been keeping stony coral reefs for between five and 10 years now and I have never once adjusted my fresh salt water due to these minor differences. ( I quit testing the salt water that I was mixing within the first six months of tank ownership.) By the end of the bucket or bag or box of salt, the differences all net out to being even.

For what it may be worth, I have almost always used Reef Crystals, with occasional switch outs to Instant Ocean.

It should also take no longer than five minutes to mix a normal amount of salt water. If it does, you may be doing it wrong.

 

[Randy Holmes-Farley]

Should I be testing the big 3 on my salt mix EVERY time before adding?

If ALK / Mag / Calc are not equal to my tanks waters I should dose them to match?

Thoughts?

If they do not match, they are most likely higher, so dosing isn't usually needed. Calcium in Instant Ocean is an exception, and may be worth dosing.

 

[Christopher Poore]

If they do not match, they are most likely higher, so dosing isn't usually needed. Calcium in Instant Ocean is an exception, and may be worth dosing.

Thank you for the response! My question was; if my salt mix parameters do not meet my tanks current parameters; do I

a) Dose the salt water before adding to the tank
b) add new mix AS IS
c) add new mix AS IS, THEN dose the tank?

 

[Randy Holmes-Farley]

Add as is, and the effect is likely to be minimal unless it is a big water change.

Changing 10% of the water with tank at 10 dKH and new salt water at 8 dKH, only drops alk from 10 dKH to 9.8 dKH.