Natural seawater to artificial

[shadyraro]

Question for the brains trust..
I’m looking to go back to mixing my own salt, I have a 350L tank and wondering what’s the easiest way to do this?
Do I have to drain all the NSW and replace it all at once or could I do it like 50% one week 50% next?

 

[EnterName]

Making two consecutive 50% water changes is not the same as performing one 100% water change:

Let's say you performed a single 50% water change (so 175L). If you take another 175L out of your 350L system, 50% of those 175L will be artificial seawater from your previous change (assuming perfect mixing). So the second change only replaces 87.5L natural seawater instead of 175L. This means 2x50% is 175L + 87.5L = 262.5L water change which is like a 75% water change at once.

However, why do you need to change so much? There is no need to replace everything so fast. Just do your routine water changes and slowly replace the natural seawater with artificial seawater. There is no reason why having both in your system would be bad in any way.

 

[shadyraro]

Making two consecutive 50% water changes is not the same as performing one 100% water change:

Let's say you performed a single 50% water change (so 175L). If you take another 175L out of your 350L system, 50% of those 175L will be artificial seawater from your previous change (assuming perfect mixing). So the second change only replaces 87.5L natural seawater instead of 175L. This means 2x50% is 175L + 87.5L = 262.5L water change which is like a 75% water change at once.

However, why do you need to change so much? There is no need to replace everything so fast. Just do your routine water changes and slowly replace the natural seawater with artificial seawater. There is no reason why having both in your system would be bad in any way.

Well I was thinking of replacing ASW during water changes but I didn’t think it would be the way to do it as I only do 20% every fortnight.
That’s why I thought maybe I should do a 100% or 50/50 would be better, but I see your point.

 

[EnterName]

I wouldn't worry about it. Just keep doing your regular water change schedule and it will be fine. It's probably better doing it slowly anyway as you don't want to stress anything with a sudden parameter change.

 

[Randy Holmes-Farley Verified Community Expert]

I agree, there’s no need to do large water changes.

Why are you switching?

 

[shadyraro]

I agree, there’s no need to do large water changes.

Why are you switching?

I’ve lost quite a few LPS corals over the last 12-18 months which is about when I switched over to NSW. It’s too much of a coincidence but there’s nothing else I can really put it down to, even tho my last ICP came back good.