Water Change Math

atschultz1 · 10/09/2013, 05:48 PM

Greetings,

I have a 30g tank in which I estimate to have 25 gallons of water. I intend to do weekly 10% water changes.

Here's the question:

My salinity is sitting at 1.021. At what salinity level should the 2.5 gallons of replacement water be to raise the salinity of the overall tank to ~1.024

If there is a known equation to figure this out please don't hesitate to post it.

I appreciate any advice you guys can provide!

ca1ore · 10/09/2013, 05:57 PM

Don't think you want to be raising the salinity all at once. Do you use an ATO? If so, just dump a cup or tow of salt into the reservoir and monitor levels in the tank over the course of the week.

atschultz1 · 10/09/2013, 06:03 PM

Quote:

Originally Posted by ca1ore

Don't think you want to be raising the salinity all at once. Do you use an ATO? If so, just dump a cup or tow of salt into the reservoir and monitor levels in the tank over the course of the week.

Thanks for the advice ca1ore. However, I am quite new to the hobby and have yet to get into ATO systems.

Without an ATO system in place, do you have any other advice on raising salinity in the tank?

devimik · 10/09/2013, 06:05 PM

Try this saltwater calculator...http://www.saltyzoo.com/SaltyCalcs/SalinityAdjust.php

atschultz1 · 10/09/2013, 06:11 PM

Quote:

Originally Posted by devimik

Try this saltwater calculator...http://www.saltyzoo.com/SaltyCalcs/SalinityAdjust.php

Thanks, devimik! That calculator is exactly what I was looking for.

Do you think that I should try to raise the salinity of the tank from 1.021 to 1.024 in one water change or over the course of a few?

schatzi · 10/09/2013, 06:12 PM

I would suggest mixing all your new water at the salinity you want and just stick with that. The tank will eventually get there. If you want it to go quicker then mix the new water at a higher level and then switch to your desired amount when the tank gets to where you want it. Or top off with saltwater for a few days, or every other day, that will get it up too.

downbeach · 10/09/2013, 06:21 PM

Use your make up water for topping off, instead of plain RO/DI until the DT is where you want it.

atschultz1 · 10/09/2013, 06:21 PM

Quote:

Originally Posted by schatzi

I would suggest mixing all your new water at the salinity you want and just stick with that. The tank will eventually get there. If you want it to go quicker then mix the new water at a higher level and then switch to your desired amount when the tank gets to where you want it. Or top off with saltwater for a few days, or every other day, that will get it up too.

schatzi,

That's a good idea. I'll probably start mixing the replacement water at the desired level and then just keep on keeping track over time. Thanks!

atschultz1 · 10/09/2013, 06:29 PM

Quote:

Originally Posted by downbeach

Use your make up water for topping off, instead of plain RO/DI until the DT is where you want it.

downbeach,

Salinify the top off water as well as the water change water? That's a good point too!

Spyderturbo007 · 10/10/2013, 07:10 AM

I would recommend against raising the salinity all at once. I have to raise the salinity of my QT tank when I get a new animal from the LFS salinity of 1.018 to my tanks salinity of 1.024. All I do is use regular saltwater for my top off instead of the normal RO/DI. This brings up the salinity very slowly and has never caused me problems.

10/09/2013, 05:48 PM	#1
atschultz1 Registered Member Join Date: Oct 2013 Location: ND Posts: 12	Water Change Math Greetings, I have a 30g tank in which I estimate to have 25 gallons of water. I intend to do weekly 10% water changes. Here's the question: My salinity is sitting at 1.021. At what salinity level should the 2.5 gallons of replacement water be to raise the salinity of the overall tank to ~1.024 If there is a known equation to figure this out please don't hesitate to post it. I appreciate any advice you guys can provide!

10/09/2013, 06:05 PM	#4
devimik Registered Member Join Date: Dec 2012 Location: KC, KS Posts: 637	Try this saltwater calculator...http://www.saltyzoo.com/SaltyCalcs/SalinityAdjust.php __________________ Mike D Coral Beauty, Green Filefish, One Spot Foxface, Springeri Dottyback, 2 Ocellaris Clowns, Yellow Watchman Goby, Flame Hawkfish, Spotted Mandarin Current Tank Info: 90g Softie Reef, 150# live rock, 30g sump w/refugium, Tunze Osmolator 3155 ATO, Octopus NWB 150 Skimmer, Mag 950 return, Maxspect 120w Razor 10K LED light X2, BRS Phosphate Reactor; Apex Lite

10/09/2013, 06:12 PM	#6
schatzi Professional amateur Join Date: Dec 2008 Location: JC, MO Posts: 513	I would suggest mixing all your new water at the salinity you want and just stick with that. The tank will eventually get there. If you want it to go quicker then mix the new water at a higher level and then switch to your desired amount when the tank gets to where you want it. Or top off with saltwater for a few days, or every other day, that will get it up too. __________________ 125g Mixed Reef, 46g predator tank, 25g fuge, 39g frag/fuge, 70g sump, 29g clown tank.

10/09/2013, 05:57 PM	#2
ca1ore Grizzled & Cynical Join Date: Apr 2006 Location: Stamford, CT Posts: 17,319	Don't think you want to be raising the salinity all at once. Do you use an ATO? If so, just dump a cup or tow of salt into the reservoir and monitor levels in the tank over the course of the week.

10/09/2013, 06:21 PM	#7
downbeach Registered Member Join Date: Nov 2006 Location: Smyrna, Delaware Posts: 3,767	Use your make up water for topping off, instead of plain RO/DI until the DT is where you want it.

10/10/2013, 07:10 AM	#10
Spyderturbo007 Registered Member Join Date: Jun 2012 Location: PA Posts: 2,564	I would recommend against raising the salinity all at once. I have to raise the salinity of my QT tank when I get a new animal from the LFS salinity of 1.018 to my tanks salinity of 1.024. All I do is use regular saltwater for my top off instead of the normal RO/DI. This brings up the salinity very slowly and has never caused me problems.