Water Change or No Water Change

[Pntbll687]

First let me say I know there are many threads on this topic (and I feel like I have read through all of them)...

I wanted to get a fresh perspective on this from the community. As a newer reefer about to set up a 150G system... I'm thinking about design considerations to make water changes easier (or even setting up continuous water change). However, I don't like doing things just because people tell me to, and not understanding it, and I feel like that's the case for water changes. Here's my thoughts... And please call me out if I'm wrong I'm trying to learn. For clarity I'm talking about regularly scheduled weekly/monthly/continuous water changes, NOT water changes when something bad happens (those make clear sense to me).

If you're using it to rid something bad. By my calculations, if you have a toxic substance introduced in your tank all at once, even if you do a 20% monthly water change, after 6 months ~30% of that substance will remain... Takeaway is if something really bad gets introduced to your tank, regular water changes isn't necessarily going to meaningfully combat it. You're better off doing huge water changes over the course of 1-2 weeks when this occurs.

If you're using it for export. To me, what is regularly produced in a reef tank environment can be naturally exported, and if you rely on water changes from my perspective it will just lower the "base consumption/export rate" of your whole system.

If you're using it to replenish. Again, same as export, all that will do is lower the "base amount" of things you need to dose into your water, because it will be replenished by new SW regularly. I don't see this as a significant benefit, because you're still needing to dose things...

The biggest problem I have is that religious water changes almost seem inherently wasteful to me. You're blowing through salt, RODI water, setting up infrastructure for it, and also dumping what could be good water down the drain.


Takeaway for me is, unless I'm convinced otherwise, I'm only going to do "emergency water changes" when something goes bad. So what are your guys thoughts... And again sorry if there's a million threads on this topic ): I really wanted to get a fresh take.

So, I have a 200g system so I can say I have comparable system.

It really depends on what type of system you run. If you're on the lower nutrient side, then water changes may impede what you're accomplishing, and could bottom out nutrients if doing large enough changes.

My system is nutrient positive (meaning nitrates and phosphate go up consistently), so I use water changes as an export. I got a 55g barrel for free, and a large jebao pump ($150 if I remember right) and some 5/8 tubing ($20?). The barrel is in my basement and the pump works, but is a little slow. I marked in a corner where to drain the water to, and can do a 30g water change with just setting up two hoses and starting a siphon.

I will say the tank does look better after doing water changes. I don't run carbon, so the water changes takes some of the yellow out of the water.

Not doing water changes is fine, but don't get caught up buying X, Y, Z to reduce this or that (gfo reactor, nitrate reactor, refugium) when doing water changes would be more cost effective and easier in the long run.

 

[Lasse]

My tank looks better with regular water changes

I do not know - but i think that my tank can´t look better - 5 years without regular WC and 4.5 years since the last large one.



According to ionic balance - this is my concentrations of the major ions after 4.5 years with Core7 - forget that concern.

Salinity 32.7 psu

Chloride ions - 17 567 mg/L (expected 18125 mg/l)
Sodium ions 10281 mg/l (expected 10090 mg/l)
Sulfate 3057 mg/l (expected 2523 mg/l)


Sincerely Lasse

 

[ifarmer]

you should be okay without having to do lots of water change since you are doing fish and live rocks only.

 

[jmichaelh7]

Think of it as a car running with no oil change. You can keep topping off oil, but eventually you’ll need to dump and replace fresh oil.

I was skipping wc but algae started growing despite refugium and skimmer . I did a big water change and a little basting. Gone .

I think water changes are a staple in this hobby

 

[Crustaceon]

I've always seen regular water changes as a way to "average" out tank parameters and keep them better balanced overall. I do a weekly 10% change on my 200g system and check alk on a daily basis. I've never had alk stay this predictable throughout the week by skipping water changes and just trying to adjust 2-part and it shows in how much encrusting i'm getting out of some newer acro frags.

 

[SteveMM62Reef]

My Concern is Airborne Chemicals in our tightly sealed homes, ending up in the tank. Cooking Mists, Bug Sprays, Deodorant, HairSpray, Bath Cleaner, and those little plug ins, which are banned in my house. Lord help you, on your health, if someone burns candles in your house.