Hot Tips: How do you perform your waterchanges?

by | Mar 15, 2007 | 0 comments

A selection of useful tidbits of information and tricks for the marine aquarist submitted by Advanced Aquarist’s readership. Readers are encouraged to post them to our Hot Tips sticky in the General Reefkeeping Discussion forum or send their tips to [email protected] for possible publication. Next month’s Hot Tip theme will be “What camera / setup do you prefer to use to photograph your tank?“.


How do you perform your waterchanges?

I change approx 15-18 gallons per week in my 130 gallon system. I mix the water on Thrusday. I do my water change on Sunday.

I have two 20 gallon roughneck containers. I have drilled in the back of my tank a 3/4″ bulkhead that is plumbed with a simple ball valve. This is my “water drainer” system. I use a Mag 5 pump in the new water containter and pump it into the sump while simultaneously draining it from my “water drainer.” The whole process takes five minutes.

Submitted by: Fishie Nut

I change about 50 gallons on my 176 gallon tank every few months (to be honest, sometimes every half year due to my laziness). The way I perform my water changes is as follows:

I manually fill a 55 gallon container with RO water, mix in salt (I use Tropic Marin Pro), and let the water circulate in the container for 72+ hours, checking to make sure the salinity matches my aquarium’s (or the desired level). The day of the water change, I add a heater to the container to bring the water temperature up to that of the aquarium’s. I then either siphon or pump out 50 gallons (pre-calculated) from my aquarium into the sink or outside drain and then pump in the new water into the aquarium. Clean up the mixing container, and I’m done.

It sounds like a lot of steps, but it’s actually a very quick and simple process. I really don’t have an excuse not to do this more often.

Submitted by: Len

Change about 45 gals – 4 times a year…..I have my RO plumbed to a 25 gal holding tank which gravity feeds to my hospital tank ( 30 gal glass), Water change tank ( water softener- plastic) and then onto the top off system in my sump. All three have shutoffs and float stops to control the levels. I keep the holding tank filled with room temp water which keeps the main system topped off. When I want to do a water change I just open up the valve and the water change tank fills itself and I add the salt. The holding tank fills itself back up after the water change tank float valve shuts off the flow.

I keep a submersible pump in the water change tank with about 12 feet of tubing. I use this to circulate the water for a couple of days and then I grab the tubing and redirect the water into my sump of my main tank. I also keep a pump with a length of plastic tubing that is mounted on the wall above the main tank which pulls water from main system into the drain or to the hospital tank – wherever the water is needed. This system does double duty for me and allows me to quickly get a hospital tank on line if needed. If it were to fail the worst that can happen is that 25 gal of fresh water gets dumped into the main tank – which is not great, but would not be the end of my display. Not sure how clear this is, but I tried.

One final note – I can not tell how many times I dumped RO water on the floor because I forgot that I was filling the water change tank – worse yet were all the times I had to dump saltwater because I over filled the main tank during top off. My wife has not complained in almost two years since setting up this system – Knock on wood all is well in the tank room!

Submitted by: danimal

On my 160 I change about 20 gallons every two to three weeks. I use two 20 gallon tubs. In one I make up the new saltwater either in the morning or the night before.

To get the water out of my tank I syphon into the other tub from the tank until the level are equal by eye ball standards. I take the chance to get any crud that was collected on the bottom. I due this step with the main pump off.

When it is time to put the water back I use a MJ1200 to pump the new saltwater into the sump where I let it run for a little while. After about 10 minutes When I am ready I close the valve on my return pump and turn it back on. I crack it open and get things going again. I feel by putting the water in the sump and letting it mix and slowly turning the pump back on it gives any unequal SG or temp a chance to balance out so I do not shock the tank.

Submitted by: Wazzel

I basically do the same, mix salt and RO water for a couple of days with a heater and a mag 5 in a 32G brute and then syphon the same amount of water out of my tank (about 22-24 gallons which equals about 25% of my tank’s volume) along with a thin layer of sand/possible detritus and then plug a hose to the output of my mag 5 from the brute and into the tank. I do with all my powerheads and return pump off. I try to do a 25% water change at least once a month, but sometimes every 2 weeks.

I wish it was more “automated” in the sense that I had a drain drilled in the tank that I could just turn a ball valve to drain it and also hook up a pump from the newly mixed salt water container and pump it back in or something similar. Sometimes, I have problems with a certain amount of water ending up on my floor – especially when pumping water back in! (I hate when hoses fall out of tanks!!! Sad ) I’m anxious to see what some of the “high tech-ies” have to contribute to this.

Submitted by: bleedingthought

My sump is under the house so I have space to be silly. Since I have the space, I like to keep water on hand incase I need it.

I have a 150 gallon rubbermaid sump, plumbed with a float valve and a ball valve to the RODI (changing to DI only because I found the water quality in our neighborhood is good), that I use for to keep water for water changes.

There is a pump for circulation, a pump for aeration and a heater in the rubbermaid. There is also a pump that pushes water to the sump.

When I need new water, I turn the ball valve and leave it open till the float valve shuts off the water. I turn on the circulation pump and the heater, and add salt over the next couple of a days to check levels of sg, ca, dkh and alk and adjust as needed.

I drain about 40 gallons (I usually change 40 gallons of the 300 evert two or three weeks) from the main system by running a hose and turning a valve. This isn’t hard plumbed because I often will use the ‘old’ water from the reef as new water for my cephalopod system. Then, I flip a switch and the pump in the rubbermaid turns on and fills the tank. Flip the switch when filled. I really should put it on a float switch and a bypass, but I think I would worry and watch the tank fill anyway.

When there is about 40 gallons left in the rubbermaid, I open the ball valve from the RODI and start again.

When the skimmer is skimming particularly wet, I can also flip the switch and top off the tank with saltwater if needed.

Submitted by: Thales

turn return pumps off. wait for sump to fill. drain sump with a pump. pump fresh saltwater into sump. turn return pumps on. A 20 gallon water change. takes about 15 mins all together. All of which not a drop spilled on the floor. very easy.

Submitted by: pwj1286

I have a ~150 gallon system. I do about 25% every 3 weeks or so.

My RO/DO runs to 2 rubbermaid tubs with heaters and powerheads. I mix in Tropic Marin for a day or 2.

I have a pump in the tank system that’s plumbed to a sink drain via a dishwasher adapter. I open a valve to the drain and flip a switch to pump out the old water.

The mixing tubs are plumbed to the tank system. So, I flip another switch to pump in the new water.

Pretty automated, or I’d never manage such regular, frequent changes.

Submitted by: ToeCutter

I mix my Saltwater in a 22G rubberbaid with two powerheads and a heater for a day or six.

Every other week when I do a water change on my 120G I turn of the CL and open a valve I have plumbed from one overflow to the house. As the water is draining I use a maxijet 1200 and hose to refill the sump. Five minutes later I am done with a 10% WC. Every six weeks I turn off the return, use siphon hose and clean the SSB. I siphon that straight to the drain as well.

On my 30G I Do a 4g WC every other week with buckets and a siphon hose.


Valve and bucket

Submitted by: trido

I open a valve just at the waterline on my sump and set a bucket under it. Then I flip a switch that turns on a pump which pumps new saltwater from my reservoir into my display. The new water is a degree and a half cooler than my display and so it sinks, displacing old water over the overflow, and down into the sump, where it goes out the valve to the bucket. After one minute I shut off the pump. A couple minutes after that the water stops flowing from the valve. I shut the valve, empty the bucket, and I’m done.


New saltwater reservoir












Submitted by: DanaCol

I have an automatic water change system. Every day, automatically, I change three gallons of water.

People spend way to much time worrying about having all sorts of different filtration methods and addatives. Well here’s a method for you. The ZooKeeper method. Change a lot of water and watch your reef thrive.

Submitted by: ZooKeeper

My 300 gallon reef has a 150 gallon sump. The sump has bulkheads in the bottom. I ran a pipe out through the wall of my house. I pump the water out of the sump and into a swamp behind my house. Then I pump the new saltwater in from a 130G vessel.

So it takes me about an hour to do a 130G water change.

I do sometimes siphon a couple of buckets of water out of the tank so that I can get the detritus out of the tank and/or refugium.

Submitted by: Louey


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