The Ultimate Water Change??

[bairdimusprime]

i do 10 gallons a week in my 60g cube. every Sunday

 

[tyler1503]

What would be really nice is a calculator that would tell you how many water changes it will take to replace all the water. So you could then decide how often all the water should be replaced. I would like to know this for my bio cube. I do water changes on it but not often if I new the amount I needed to change to keep the water in it 100% replaced every 3 months I'd most likely do it.

Anybody good at math know how to build this type of calculator?

If my maths is right (doubtful ) you would have to do 20% water changes once a week for 16weeks. I know that's about 4 months, not 3 like you asked for but I don't want to do the math again lol. So maybe closer to 25%?
It's not quite 100% of the old water that has been removed, you'll be left with 2.8% of the original water. But that 2.8% has been diluted with new water to the point it's not noticeable anymore. I hope that's right lol.

 

[ssdawood]

What would be really nice is a calculator that would tell you how many water changes it will take to replace all the water. So you could then decide how often all the water should be replaced. I would like to know this for my bio cube. I do water changes on it but not often if I new the amount I needed to change to keep the water in it 100% replaced every 3 months I'd most likely do it. Anybody good at math know how to build this type of calculator?

Hey bud how do you maintain such low levels of phosphates with so much feeding. Also by little or no water changes do you dose anything else.

 

[Keithcorals]

My only filtration is a refugium and a skimmer if things are balanced right and the refugium is setup the right way it's all you need.

Found what I was looking for

 

[Keithcorals]

For me that math would make it seem any less than 20% a week would take too long to replace possibly depleted elements. I think this is a wY better way of deciding on what size water change to do than just guessing what is needed. At least this wY you know how often the water is replaced. If you did a 20 once a month it would take a year to replace a little over 90% of you water

 

[Diesel]

It's getting interesting...........
In order and we all know to come close even just a little, we need to do constant WC trough out the day.
We all know that will be almost impossible.
Heck, that's why we invented the skimmer, sump, reactors of all kind to help us to stay close with the desired balance our corals can live in.
By doing so and to trust our equipment we putting our reef system on the edge of failure some more than other.
Because of that we test a lot, testing is a big part of the hobby.
Nothing new here!
Just take a dive on a reef and look for your self what you see................
One thing we agree on is a massive WC every 1/10 if not 1/100 of a second!
Can we get even close to that?
We try to by as I mentioned to have as much as possible equipment on our tanks to help us with that.
We forget that most corals and fish are getting used to being in a balanced system.
What works for you doesn't need to work for some one else.
We kind of are entrepreneurs in a way to create your own signature reef in your on mind, are we?
The fact of the matter is that if you take a look at your reef after you do a WC and you see your corals responding positive on that WC you know you were due way before that.
If I do a WC my corals look the same as before and had the max PE already.
Some ppl pushing it on a few other things as well, with changing the light bulbs or the carbon/GFO in your reactor.
It's not up to me to tell you to change that on a regular schedule but we all know.
Key points as mention before is, Balance, consistency and if you make it your own, a simple task as a WC should be that complicated.
It's like brushing your teeth, you do it not because your dentist tells you.
You do it cause you know it's the life of your teeth.

I'm sure I missed some key factors but that's why we have this discussion.
A lot of good things are mention already and we just need to keep it coming.

 

[Keithcorals]

Now I'm considering doing water changes on my big system but I would need a salt with a lower alk. I run mine at around 7 and having it move isn't a good thing. So does anybody know a good salt with a alk of 7-8 ?

 

[Diesel]

Now I'm considering doing water changes on my big system but I would need a salt with a lower alk. I run mine at around 7 and having it move isn't a good thing. So does anybody know a good salt with a alk of 7-8 ?

That's one of my points that Paletta and me agree on is small WC.
You will upset your # in your tank far less than a big WC.
You can do the math, if you have a 200 gallon system and do a 40 gallon WC once per week or you do 20 gallon twice a week.
If you make it easy on yourself to do a WC the less you hate it and the more you do it.
Hey, where did I hear that before?

Btw, Oceanic is a salt that is about 8 in ALK.

http://www.oceanicsystems.com/products/scientific-grade-marine-salt.php

 

[cope413]

Two 20g weekly WC is not the same as (1) 40g WC. If you'd like, I can make you a very simple calculator in excel... Just let me know what, specifically, you'd like to calculate and what variable you want to be the driver.

 

[revhtree Verified Admin]

I'm loving this thread already.

 

[AJsTank]

My system is 470 gallons - I do 10% a month - 5% twice a month

 

[loreef]

My system is a 30 gallons (less rocks and sand), I change 5.4 gallons every Sunday night.
That's a 20% change per week.

 

[The griz]

I have an 80 gallon with a 30 sump. I do 10 gallons twice a week. Takes a few minutes. Basically I pump 10 out of the dt while my wife pumps 10 into the sump. Total down time is roughly 6 minutes.

 

[that Reef Guy]

I do Massive Weekly Water Changes with no Problems.

55 Gallon - 28 Gallons a Week Changed
29 Gallon - 12 Gallons a Week Changed
20 Gallon - 8 Gallons a Week Changed
10 Gallon - 4 Gallons a Week Changed

So all my Aquariums get about 70 Percent of the Water Changed Out with Water Displacement From the Rock, Sand, and Corals.

 

[cope413]

My system is 470 gallons - I do 10% a month - 5% twice a month

You actually don't do 10%/month if you do two 5% changes.


To avoid getting into crazy detail, think of it this way...

Let's say you have 10ppm Nitrates in your system and you do a 5% WC.

After the WC, theoretically, you should be at 9.5ppm (10ppm * (1-WC%))

Now, if you were to do another 5% change, immediately after, you would be at 9.025ppm NO3 (9.5 * (1-WC%))

So with 2 5% changes, you would have reduced your NO3 by 9.75%

If you were to do 1 10% change, you would, theoretically, be at 9ppm - a full 10% reduction.

So with Two 5% changes, you are losing .25% of the potential waste/pollution reduction that a single 10% WC would give you.


Two 10% changes would get you from 10ppm to 8.1ppm
One 20% change would get you to 8ppm.

So you're losing 1% of the potential reduction...

This loss in waste/pollution reduction potential increases as your WC% increases. (2) 25% WC vs (1) 50% WC = 6.25% loss in potential.

 

[zesty]

15 gal twice a month with 60DT & 40sump
I dose the new water with alk to match the alk that is currently in my system.

 

[FLipp]

57gal:
weekly 5-10 gallon water change.
same on the 60gal.

 

[mrcoffee2]

I change my water every 6 months or so, and even then that's not necessary... I could probably get away with never doing a WC... I skim and add tropic marin to my ATO water. Since I have adopted this model everything thrives.

IMHO water changes are expensive and can be avoided if you know how to properly dose.

 

[FishDooD65]

I change 8 gallons every two weeks in my 55 gallon reef tank. I feed fish and corals every other day.

 

[gpdno]

I have a 150 gal DT with a 5 gal refugium. I have an automatic water change that run three nights a week. I replace about 4 gals a night so 12 gal a week.
I dose a minimum amount of calcium and alk. Magnesium is not depleted faster that the water change can replace.