280ish gallon AWC

[mr9iron]

I am looking for some opinions from others who utilize a continuous water change system on their tank. The 280 gallon tank is almost finished cycling, and I have setup a Neptune DOS for a continuous water change. My NSW tank will hold 25 gallons as well.

My initial bioload is going to be very light to say the least. I have in QT a blue tang (Paracanthurus hepatus), cleaner wrasse (Labroides dimidiates), and a Orange Diamond Goby (Valenciennes puellaris) which will be ready for the display in a couple of weeks.

They will be fed via the Neptune AFS with NLS pellets, and some flake food 3 times daily. Once or twice a week I will also give them a small cube of Black Jacks Reef Crack for some meaty food.

I have considered changing out 3 gallons a day, which equates to roughly 84 gallons monthly or 30%. Would this be too much of a change, and should I start lower? I have always just changed out X gallons weekly on my tanks, but the AWC is new to me. Thoughts?

 

[slief]

Given your load, 3 gallons may be more than needed but there is more to this equation than just the load and tank size.

I have a 480g display, 650g overall volume and over 60 fish. Many of wish are over 7" long. I feed 3 times a day and have what I consider to be reasonably heavy load. I change out 5 gallons a day via my Genesis Renew and it keeps my tank very happy and healthy. That said, I also have several hundred pounds of live rock, a well sized refugium with a deep sand/mud bed as well as a smaller display refugium the combination of which provides for good denitrification as well as nutrient export. I also run four 7" filter socks and have a very efficient hard working skimmer to removed dissolved organics. The combination of all of the above helps to reduce my water change requirements as I have good mechanical and biological filtration to help remove waste, organics and nutrients.

In my opinion, you have to do some trial and error. Every tank is different and because of that, it's next to impossible for anybody to quantify what is truly "needed". The amount of live rock/bacterial surface, skimmer, refugium vs no refugium, socks etc will all play a role in your systems health. Then their is the uptake of elements by corals and how you are supplementing them whether through dosing, calcium reactors or water changes.

Let the health of your tank and test results determine your water change amounts. Given your light load, I'd probably start at 2 gallons a day and see how your tests look after a few months of running that way. You might even be able to get away with less but that's a good starting point in my opinion. Also keep in mind that since this is a new tank, your still going to be working your way to maturity over the next several months as your bacterial populations diversify and build up. You will likely find that as that happens, your needs for water changes may lessen for the same size load.

 

[slief]

I will also point out that I have found daily water changes to be much more effective when it comes to keeping a tank healthy than weekly larger water changes because nutrients don't build up in the tank over the course of a week. I rarely ever do a larger water change. Once ever 4-6 months I will kick off a 40 gallon water change just for piece of mind and because I can do it with the push of a button. I don't do it because it's needed. My nitrates are always 0 and I never have nuisance algae in my display. Like I said, it's just a piece of mind thing. I also keep my tank primarily bare bottom so I don't need to vacuum and I have an insane amount of well controlled and well planned flow to insure that waste doesn't settle on the bottom.

 

[Sethjamto]

I change only 1.5 gallons a day in my 300 and the tank is healthy and beautiful with zero algae buildup at all. I'm doing that water changes with a Litermeter III setup. Have been doing 1.5g's for about a year and a half. I started small with the intent of building up to 3g's a day, but found that I never had to increase the amount.

 

[mr9iron]

Given your load, 3 gallons may be more than needed but there is more to this equation than just the load and tank size.

I have a 480g display, 650g overall volume and over 60 fish. Many of wish are over 7" long. I feed 3 times a day and have what I consider to be reasonably heavy load. I change out 5 gallons a day via my Genesis Renew and it keeps my tank very happy and healthy. That said, I also have several hundred pounds of live rock, a well sized refugium with a deep sand/mud bed as well as a smaller display refugium the combination of which provides for good denitrification as well as nutrient export. I also run four 7" filter socks and have a very efficient hard working skimmer to removed dissolved organics. The combination of all of the above helps to reduce my water change requirements as I have good mechanical and biological filtration to help remove waste, organics and nutrients.

In my opinion, you have to do some trial and error. Every tank is different and because of that, it's next to impossible for anybody to quantify what is truly "needed". The amount of live rock/bacterial surface, skimmer, refugium vs no refugium, socks etc will all play a role in your systems health. Then their is the uptake of elements by corals and how you are supplementing them whether through dosing, calcium reactors or water changes.

Let the health of your tank and test results determine your water change amounts. Given your light load, I'd probably start at 2 gallons a day and see how your tests look after a few months of running that way. You might even be able to get away with less but that's a good starting point in my opinion. Also keep in mind that since this is a new tank, your still going to be working your way to maturity over the next several months as your bacterial populations diversify and build up. You will likely find that as that happens, your needs for water changes may lessen for the same size load.

Silef,

Thank you for the very detailed information. I am beginning the tank with roughly 100 lbs of dry rock that I have built into an open aquascape. I am kind of bothered by this as I have always used quite a bit in my past tanks. I wanted an open scape with several small fishes combined with some LPS, and some of the easy or more forgiving SPS. I have considered placing a Marinepure block in the fuge to increase surface area for denitrification as well.

I do have Tropic Eden Reeflakes in the tank at a depth on 1.5 to 2 inches. My plan is to vacuum this once monthly, and I chose a larger grain sand so that I could increased, turbulent flow. I am currently playing around with different configurations of my Gyre and Jebao powerheads and will see how this goes.

The tank is filtered via a LifeReef LF1-300S and skimmed via the LifeReef SVS24. A LifeReef Reefugium is also connected to the system, and I plan on running some deathstar cheato like D2Mini.

I will also point out that I have found daily water changes to be much more effective when it comes to keeping a tank healthy than weekly larger water changes because nutrients don't build up in the tank over the course of a week. I rarely ever do a larger water change. Once ever 4-6 months I will kick off a 40 gallon water change just for piece of mind and because I can do it with the push of a button. I don't do it because it's needed. My nitrates are always 0 and I never have nuisance algae in my display. Like I said, it's just a piece of mind thing. I also keep my tank primarily bare bottom so I don't need to vacuum and I have an insane amount of well controlled and well planned flow to insure that waste doesn't settle on the bottom.

I really like the idea of the daily/continuous water change idea as it just seems to make sense to me. I think I will start with a gallon daily, as my bioload will be pretty light with just 3 fishes. More will come, but only after they have spent the appropriate period in qt. Same for the coral.

I change only 1.5 gallons a day in my 300 and the tank is healthy and beautiful with zero algae buildup at all. I'm doing that water changes with a Litermeter III setup. Have been doing 1.5g's for about a year and a half. I started small with the intent of building up to 3g's a day, but found that I never had to increase the amount.

Sethjamto,

This is great to hear. I would like to know more about your system. Do you have a build thread?