Water changes really necessary?

[Zeeter]

So here's the thing. My nitrates are extremely low and always have been except for a spike right after the cycle. I am dosing calcium, dKH, and magnesium along with trace elements.
I have the equipment to run a continuous water change, but haven't set it up yet. That said, if my parameters are in line, is there really any need to do water changes? The only thing I've done was replace about 30 gallons in my 180 while doing some maintenance due to a problem with my ATO. That was a couple of months ago.
I'm thinking, if everything is reading positive then why mess things up with a water change?

 

[rtparty]

If a water change “messes things up”, you’re doing them wrong IMO

They provide loads of benefits over the life of a tank. I’d look at more fish or feeding heavier if you really can’t keep nutrients up

 

[Nonya]

I haven't done a water change in 5 years in my SPS tank; HOWEVER, I dose Ca, Alk, Mg and supplement with trace elements. MOST IMPORTANTLY, I periodically send in a sample to Triton Labs for testing to verify that I'm still on track. I would never assume things will continue to go well in the future because they're fine today. Reef inhabitants consume trace elements, and if you don't test, you won't see the crash that's sure to happen.

 

[t5Nitro]

Haven’t changed water in a mixed reef in about 3 years or more now. I dose kalkwasser and AFR.

I keep telling myself I’ll change out 10 gallons one day to start using up salt that I have but it hasn’t happened yet. Maybe over my next vacation block.

 

[Zeeter]

If a water change “messes things up”, you’re doing them wrong IMO

They provide loads of benefits over the life of a tank. I’d look at more fish or feeding heavier if you really can’t keep nutrients up

If you're not doing water changes and you're dosing, then after the water changes you have to adjust your dosing to compensate for the nutrients you added in the water change. In other words, it messes things up. Not horribly, but more so than by not doing a water change at all.

 

[Randy Holmes-Farley]

If you're not doing water changes and you're dosing, then after the water changes you have to adjust your dosing to compensate for the nutrients you added in the water change. In other words, it messes things up. Not horribly, but more so than by not doing a water change at all.

What nutrients are you adding by water change?

Water changes clearly arent necessary, but the better question is whether they are useful, which I’d argue they often are.

 

[rtparty]

If you're not doing water changes and you're dosing, then after the water changes you have to adjust your dosing to compensate for the nutrients you added in the water change. In other words, it messes things up. Not horribly, but more so than by not doing a water change at all.

What nutrients are you adding in a water change? Or do you mean elements?

A 10% water change will not significantly impact any element enough to mess things up. For example, if you run your alkalinity at 8dkh and use a 10dkh salt (just for this example), after you change 10% of your water your alkalinity will be 8.2dkh. Test kits aren’t accurate or reliable enough to pick that up and your corals certainly don’t care. The impact is even less if you use salt that matches your parameters to begin with

 

[El Toro]

If you're not doing water changes and you're dosing, then after the water changes you have to adjust your dosing to compensate for the nutrients you added in the water change. In other words, it messes things up. Not horribly, but more so than by not doing a water change at all.

Not nutrients but as @critsaid, trace elements.

I do a 10% change each month when I maintenance my cannisters. I dose Trace and aminos 3-4 times a week along with some Reef Roids. My Nitrates are consistently 5ppm and my Phos range from .05-.25 which I imagine means Phos uptake is happening alomg the way.

My chem profile is below in my Sig for reference.

 

[VintageReefer]

I haven’t done a water change in 2+ years. I don’t run a skimmer either. I give credit to an algae turf scrubber + all for reef

 

[Macbalacano]

Are they necessary or an absolute must? No.

Can they be a helpful tool in your toolkit? Yes.

Depending on your system and goals, you likely may or may not benefit from it as much. When I had a larger tank, I didn't feel them as necessary. Now I run a 15G nano with about 40+ corals and I find them very necessary.

 

[Nonya]

Not nutrients but as @critsaid, trace elements.

I do a 10% change each month when I maintenance my cannisters. I dose Trace and aminos 3-4 times a week along with some Reef Roids. My Nitrates are consistently 5ppm and my Phos range from .05-.25 which I imagine means Phos uptake is happening alomg the way.

My chem profile is below in my Sig for reference.

Nobody is telling you not to do water changes. My last water test showed everything in the green (except for calcium because I ran my calcium dosing jug dry for a week without noticing). That's 5 years without a water change.

 

[VintageReefer]

Let’s see pics of these water change free tanks!

 

[Widdlyscudds]

IMO it's not so much what you might be adding but what you are taking away. Over time it is inevitable that certain pollutants will begin to build up within your tank, most minor or negligible but some can be serious depending on what it is. The solution to pollution is dilution. There are plenty of folks running successful systems with no water changes but just as many if not more being successful with water changes, really a matter of opinion especially on a larger system such as yours

 

[kevgib67]

I’m one of those weirdos who enjoys doing a water change. 12.5% weekly. I really enjoy the extension, color and overall happiness of my corals an hour or two after. That’s just me, I’ve been doing weekly water changes for over 18years I’ve been in this hobby. Now if I were running a tank over 100g , time and price, I might be singing a different tune.

 

[Zeeter]

What nutrients are you adding in a water change? Or do you mean elements?

A 10% water change will not significantly impact any element enough to mess things up. For example, if you run your alkalinity at 8dkh and use a 10dkh salt (just for this example), after you change 10% of your water your alkalinity will be 8.2dkh. Test kits aren’t accurate or reliable enough to pick that up and your corals certainly don’t care. The impact is even less if you use salt that matches your parameters to begin with

I said nutrients but meant elements like calcium and magnesium. The sea salt will add these elements to the tank while I am also dosing them.