Water changes

[coralreefexplore]

How often do you do these? How much percentage is a good amount? Wanted to ask and see what others think. Thanks

CoralReefExplore

[ramsey]

It depends on the tank. For my 38g and 12g, 10% once a week. When I had the 185g set up, I tried various WC schedules and had the best results changing 5g twice a week. When it gets set up again, it'll probably be 5-10g twice a week but it'll be automated this time. :D

All in all; I think the most important thing is stability. If your tank's alk runs at 6dkh, and your NSW is 12dkh, changing twenty percent could cause an alk spike. You can figure out how much it'll effect by some crude math:

(x * y) + (n * c)

x = decimal percent of water to change (for example, .1 for ten percent)
y = alk/calc/whatever of make up water
n = Decimal percent of water left in the tank (for example .9 for ninety percent)
c = alk/calc/whatever currently in the tank

So with our example, if your going to change 20% of your water with NSW that has an alk of 12, and your tank has alk of 6, the following would give you the answer:

(.2 * 12) + (.8 * 6) = 7.2dkh which will cause a spike and might make things angry.

Again, this is a crude way of doing it since there's a lot more factors (mostly chemistry) involved. A math or chemistry nerd may be able to correct me.

When I figured this out though, I realized why stuff acted mad when I did a big water change with a high alk salt. Now I use salt with lower alk and everything looks great after a WC.

[Scutterborn]

Umm, what that dude said!!^^^^

:)

Small consistent changes really are key. The volume of the change depends on your total system volume.


- Ben -

[Sherita]

It depends on the tank. For my 38g and 12g, 10% once a week. When I had the 185g set up, I tried various WC schedules and had the best results changing 5g twice a week. When it gets set up again, it'll probably be 5-10g twice a week but it'll be automated this time. :D

All in all; I think the most important thing is stability. If your tank's alk runs at 6dkh, and your NSW is 12dkh, changing twenty percent could cause an alk spike. You can figure out how much it'll effect by some crude math:

(x * y) + (n * c)

x = decimal percent of water to change (for example, .1 for ten percent)
y = alk/calc/whatever of make up water
n = Decimal percent of water left in the tank (for example .9 for ninety percent)
c = alk/calc/whatever currently in the tank

So with our example, if your going to change 20% of your water with NSW that has an alk of 12, and your tank has alk of 6, the following would give you the answer:

(.2 * 12) + (.8 * 6) = 7.2dkh which will cause a spike and might make things angry.

Again, this is a crude way of doing it since there's a lot more factors (mostly chemistry) involved. A math or chemistry nerd may be able to correct me.

When I figured this out though, I realized why stuff acted mad when I did a big water change with a high alk salt. Now I use salt with lower alk and everything looks great after a WC.

Alrighty then............:hypnotyized::hypnotyized::hypnoty ized:

I think I just pulled a brain muscle.

[hobogato]

i do 5 gallons twice a week on total volume of 250 gallons.

[Big_Pun]

i do 20-30g on a 150g system every month or two, usually 2 lol. i hate water changes.

[350gt]

Ive been doing 30 gallons every week to combat some issues on about 130 of total water volume.

i was fine with 30 bi weekly or every 3 weeks but tried to take it down to 20 bi weekly and thats when the problems started.. Tank os looking better everyweek....


alot has to do with your bioload too, i have 5 tangs in my 5' tank with a few other fish so they poop alot....

[coralreefexplore]

Ok. So I am doing everything absolutely wrong. I have 2 tanks. On my 30 gallon I am changing 10 gallons every 7-10 days. And on my 24 gallon I am changing 10 gallons every 7-10 days. Am I really doing that bad?

CoralReefExplore

[footballdude2k3]

I'm still working on my schedule, but right now 20% every other week, my friend up north with 1800 gallons does 200 gallons once a month, but has an industrial skimmer and a calcium reactor to maintain proper levels. There are a ton of ways to work it out, play around and see what works best for you.

[footballdude2k3]

It depends on the tank. For my 38g and 12g, 10% once a week. When I had the 185g set up, I tried various WC schedules and had the best results changing 5g twice a week. When it gets set up again, it'll probably be 5-10g twice a week but it'll be automated this time. :D

All in all; I think the most important thing is stability. If your tank's alk runs at 6dkh, and your NSW is 12dkh, changing twenty percent could cause an alk spike. You can figure out how much it'll effect by some crude math:

(x * y) + (n * c)

x = decimal percent of water to change (for example, .1 for ten percent)
y = alk/calc/whatever of make up water
n = Decimal percent of water left in the tank (for example .9 for ninety percent)
c = alk/calc/whatever currently in the tank

So with our example, if your going to change 20% of your water with NSW that has an alk of 12, and your tank has alk of 6, the following would give you the answer:

(.2 * 12) + (.8 * 6) = 7.2dkh which will cause a spike and might make things angry.

Again, this is a crude way of doing it since there's a lot more factors (mostly chemistry) involved. A math or chemistry nerd may be able to correct me.

When I figured this out though, I realized why stuff acted mad when I did a big water change with a high alk salt. Now I use salt with lower alk and everything looks great after a WC.
Your math is right, but there is much less of a spike if you dose and keep things consistent.

[Paul28]

5 to 10 week :)

[envy]

2 gallons a week for my 14 gallon biocube using kent marine salt