When to water change?

[gajeep94yj]

Newbie here so go easy.....

What are the guidelines for determining when a water change is needed? My tank has only been up for a few months now and I have done one water change. I have a 35 gallon display tank and a 20ish gallon sump. I swapped out 14 gallons.

For no real reason I picked up anther 14 gallons of water while at the fish store. So when do I need to change the water? My water test came back fine when they tested it at the store.

Are there any guidelines as to when I should change water?
What am I trying to accomplish with a water change?
How often and how much should I routinely change?

 

[saltbubbles]

You will get different answers for these questions but to my limited knowledge, here you go:

Water changes are recommended 10%weekly or 20%biweekly by some, including me. The reason for this is to remove nutrients, maintaining water quality, supplying trace elements for which we don't routinely test.

Others will say that as long as your params are spot on, you shouldn't mess with your tank. It works for some.

That's my humble opinion.

 

[jbdreefs]

I attempt to do 10% per week for the reasons stated above.

 

[gajeep94yj]

10% of total volume or of the display tank?

10% of the display tank is only 3 gallons for me. I think I have that much evaporate.

 

[myreefclub0070]

No corals, 2 fish, I'd test the water until your perimeters start changing so not the waste salt and water, or you can do the routine thing above which is the safe way.
Freshwater for top off and saltwater for change of total volume.

 

[porpoiseaquatics]

I have roughly 200 gallons in total water volume. That's a 180 display and about 40 gallons in sump however I lose probably 20 gallons to displacement from the sand and live rock. I change 20 gallons on a weekly basis. As stated above, my water would test fine but the trace elements are used by the living creatures and we don't test for those nor do we (in general) replace them on a regular basis. The only way to accomplish this is by changing the water.

Do this test.....take 2 solid white buckets.....fill one up with freshly made saltwater. Take the second one and fill it with water from your tank. Now set them side-by-side. I'm willing to bet that the tank water is yellow in the bucket. Your eye can't detect it when it's in the tank but against a pure white background it will show up. That's an indication that the water is "dirty".

Now having said all of that, there are some reef creatures that will prefer dirty or older water rather than clean, fresh water.

 

[rdnelson]

saltbubbles;991531 wrote: You will get different answers for these questions but to my limited knowledge, here you go:

Water changes are recommended 10%weekly or 20%biweekly by some, including me. The reason for this is to remove nutrients, maintaining water quality, supplying trace elements for which we don't routinely test.

Others will say that as long as your params are spot on, you shouldn't mess with your tank. It works for some.

That's my humble opinion.

Agree completely. Get in the habit now of regular routines. As you learn more you can adjust accordingly but now is the time to get used to the regiment.

 

[gajeep94yj]

MYREEFCLUB0070;991541 wrote: No corals, 2 fish, I'd test the water until your perimeters start changing so not the waste salt and water, or you can do the routine thing above which is the safe way.
Freshwater for top off and saltwater for change of total volume.

Four fish now

Two clowns, one Bandai cardinal, one fire fish. A cleaner shrimp too!

 

[redstang]

GaJeep94YJ;991540 wrote: 10% of total volume or of the display tank?

10% of the display tank is only 3 gallons for me. I think I have that much evaporate.

Not trying to be insulting but make sure that you are completely clear on this. Evaporation takes nothing bad with it. It's simply water leaving your tank. Nitrates, phosphates, salt, minerals, everything else stays in. When you replace the eval water with pure RODI water you're simply keeping salinity stable. So replacing evaporated water is not ever considered a water change.

When I had my 29gal biocube up I did 5gal's per week so roughly 20%. Probably way overkill. Now with a 60gal cube and 20gal sump I do, drum roll, 5gal's per week. Generally once per month I'll do ten. I estimate about 65gal total water volume after sand, rock, and equipment is considered.

 

[fishtank]

I would strongly advise getting an ATO for the evaporation. I am only a year in myself and learning new things every day. I was doing larger 20%ish water changes every 2 weeks, now that I have a few more corals I prefer 10% every week to keep things like calcium a little higher. If I had time I could do 4 gallons every 3 days and I think my system would be very happy! If I had more money I would get more things like reactors etc etc. All a balance of money vs time vs fun etc etc.

 

[jennm]

Saltbubbles summed it up nicely, regarding regular water changes.

In my experience, fudging on it and not doing them, will only lead to trouble down the road.

I'd also add - when you change water, vacuum the substrate. The purpose of water changing is to export waste. If there's all kinds of poop in the substrate, it's not being exported, and eventually it will break down into nitrogenous waste. An ounce of prevention is well worth it versus the pound of cure later on.

And as RedStang pointed out, evaporation replenishment does nothing for water quality except balancing out the specific gravity. Water evaporates, salt doesn't, nor does nitrate, phosphate or any other waste product. DO top off the tank before you do the water change, because if you replace more saltwater than you remove, you will cause specific gravity to increase over time. IE you change vacuum out 8 gallons, but replace it with 10, because the water was low when you started. I've seen that happen and people who don't keep an eye on their SG find it climbs. That can become problematic too.

Jenn