Large Tank Water Change Schedule

[offshored]

Hey guys I'm just curious what your water change schedule is?

I'm in the process of setting up a 450 (123x28x30") with ~ 190 gallon sump. Will also have ATO hooked up to RODI. Around 1/2 of the sump will be used as a fuge as well.

I was thinking I could do a 10% change every 3 weeks. Thoughts?

Will be very low bioload at first:
Small Yellow Tang, Small Purple Tang, Small Yellow Bellied Blue Tang, Oc. Clown and Black Ice Clown

Coral:
Small SPS Frag, LPS Frag, Small/Medium Frogspawn, Small/Medium Torch

New fish will be introduced one/two at a time after 4-6 week QT period after the tank is up and running.

Thanks :beer:

 

[ridetheducati]

Size of tank does not matter. Change 5-10% per week to replenish trace elements.

 

[Newbie Aquarist]

I do 10% weekly for that reason. Plus it saves on dosing meaning you wont have to use much. But you will use it.

 

[sfsuphysics]

See I fall on the other side of the spectrum, I'm not a fan of water changes that are a fixed amount regardless of bioload.

My thought on this is if you have the same fish, and the same corals in 100g tank as you do in a 1000g tank you will have 10x slower depletion of everything in the 1000g tank (a bit smaller mind you as I'm neglecting total surface area for stuff like coraline to grow). As a result you can reduce the size of your water changes, or reduce the frequency.

a 3-4 week WC schedule would be fine IMO, especially when those corals are small frags. As they get larger, maybe up it a bit, since the bioload will more likely than not be mostly coral based if you don't get more fish.

 

[sfsuphysics]

I do 10% weekly for that reason. Plus it saves on dosing meaning you wont have to use much. But you will use it.

This is only true if the salt you use actually is where you want your calcium and alkalinity (and magnesium) to be. I know a lot (most?) salts are extremely deficient in one element or more in this regards.

For instance, if you use Instant Ocean I think that mixes to like 330ppm in calcium, well if you have a doser/CalRX/etc and keep your calcium at 400ppm, then each water change actually takes calcium out of the system, meaning you have to dose more.

 

[offshored]

4 weeks would be great... maybe just at first.

I do plan on getting some larger tangs, but not going nuts on fish count.

I've never kept a ton of coral, so I'll get into that slowly.

Guess it depends on how much of both fish and coral (sps) you want to keep.

I've been doing 10-20% every 2 weeks on the small tank... just because it's easy.

 

[Newbie Aquarist]

This is only true if the salt you use actually is where you want your calcium and alkalinity (and magnesium) to be. I know a lot (most?) salts are extremely deficient in one element or more in this regards.

For instance, if you use Instant Ocean I think that mixes to like 330ppm in calcium, well if you have a doser/CalRX/etc and keep your calcium at 400ppm, then each water change actually takes calcium out of the system, meaning you have to dose more.

But if you bump your mixing salt to the parameters you need then you wont deplete your calcium. I should have said that previously.

 

[sfsuphysics]

But if you bump your mixing salt to the parameters you need then you wont deplete your calcium. I should have said that previously.

Yes of course, but not everyone does it

I'm guilty of this myself, but I use Salinity salt, look at the bucket.. go "yeah that's good enough" and mix and change

 

[bobkill]

Use as much automation as possible so u don't have to lug all that around

 

[ridetheducati]

This is only true if the salt you use actually is where you want your calcium and alkalinity (and magnesium) to be. I know a lot (most?) salts are extremely deficient in one element or more in this regards.

For instance, if you use Instant Ocean I think that mixes to like 330ppm in calcium, well if you have a doser/CalRX/etc and keep your calcium at 400ppm, then each water change actually takes calcium out of the system, meaning you have to dose more.

This is a different topic. We are talking about water changes, not appropriate water changes for purposes of providing Mg/Alk/Ca.

 

[offshored]

Only thing I can't automate is the removal of the old water. Will have to lug that away to dispose of.

 

[dave.m]

You have not provided us with any information as to what you have already read, so I offer the following link just as a suggestion in case you haven't seen it before.

Water Changes in Reef Aquaria - Randy Holmes-Farley - Reefkeeping Magazine

Dave.M

 

[slief]

I have as Litermeter III that I use for automatic waterchanges on my tank. My overall water volume is around 580 Gallons or so. I have my Litermeter setup to remove and replace 25 gallons per week. My tank isn't heavily stocked but I do have 30 or so fish in it which I feed every other day, sometimes more sometimes less as there is an abundance of pods, small shrimp and other stuff for them to forage on.

With my tank, having the automatic water change system is an important aspect for me as I am kind of lazy. That said, I have never ever had a water quality issue even when I wasn't doing water changes for years. That said, during that same period, I was not feeding the fish either. They kept themselves fat and happy as I have enough live rock in my system (nearly 1000 pounds between the display and sump) to insure that there is plenty of biological filtration and lots of little critters that reproduce making for a sustainable food supply. I also attribute my water quality of the years to having great protein skimmers.

 

[smb2415]

SLIEF - not to hijack the thread but I've been looking for skimmer recommendations from others with 450g+ I am setting up a 550g DT and ~150-200g sump/fuge. Please PM me as to not divert the thread.