Water Change - Little and often or big once a week

[G8zzaj]

Hey Everyone,

I have 3 tanks at home a 180G, 150G, 75G and am currently doing a 70% weekly change on the 180G, 50% on the 150G and 30% on the 75G.

This obviously leads to big quick changes in the nitrate level etc..... I also live in Dubai and in the summer months I have to fill tankers up and leave them to cool down for 24/30 hours before doing the weekly changes and this is a pain and the wife isn't keen on having a bunch of blue containers around the house.

I have a few questions:

1) I wanted to understand if changing 20% daily on the 150 and 180 would keep the levels more stable and still keep nitrates at a nice controllable level?
2) Prime dosing, will I dose enough for just the water change or the whole volume of water in the tank each day?
3) I have 2 FX6 canisters on both tanks, would adding a sponge filter to each make much difference to water clarity and nitrates?

 

[ken31cay]

1) I wanted to understand if changing 20% daily on the 150 and 180 would keep the levels more stable and still keep nitrates at a nice controllable level?
2) Prime dosing, will I dose enough for just the water change or the whole volume of water in the tank each day?
3) I have 2 FX6 canisters on both tanks, would adding a sponge filter to each make much difference to water clarity and nitrates?

Here's my opinion:

1) 20% wc will keep the water parameters more stable so if that was an issue then this will help. After you do a 20% wc then check the nitrate level to determine if you need to change more water. IMO you should change water as your nitrate reaches 20ppm and your nitrate level should not be higher than 10ppm after the water change and preferably 5ppm or below.
2) You should dose enough Prime to cover the entire volume of water, not just for the amount of water you are changing.
3) It will not affect nitrate levels (it will not decrease nitrates) but it may potentially cause your water to be clearer.

 

[RD.]

Looking at your tank stock in the 180, if those fish are anywhere near mature, you should probably be doing a large water change 2-3 times a week. And planning on a tank upgrade. Nitrate levels will give you a good idea of what the rate of metabolic waste is at. Which you didn't post? Use that as your measuring stick on overall waste. Adding filters won't help. Fresh water, will. If you can, look into getting Seachem Safe, instead of Prime. (for chloramine treated tap water) If you only have to deal with chlorine treated tap water year-round, consider using sodium thiosulfate. Good luck with the wife.

 

[duanes]

Your water changes schedule may depend on the alkalinity (buffering capacity) of your tap water.
If you have tap water with low alkalinity it may not resist the waste acids your fish produce.
an example might be if your alkalinity tests out at 20ppm, 2 days after a water change, your pH may have dropped fro 7.5 to 6.
In this case it may be more important to do every other day 30% water changes to maintain stability.
If your water has a higher alkalinity, it will resist change and it may take a week to budge even a 10th.

But another factor to consider is nitrate.
If you are heavily stocked, is smallish, or if you have large fish your nitrate might rise from 5ppm to 40 ppm 2 days after a water change.
If this is the case, a 30% water change every other day might be in order.

But if you have a large tank with i.e. 20 cardinals, a Betta and a few Corys and the tank is heavily planted, and nitrate remain below 10ppm for at least 2 weeks, your testing is telling you that might be the schedule for you.

Your schedule may also be influenced by the type fish you keep, some species, if kept in water they have not evolved to live in, become prone chronic to infections like HITH or bloat due to bacteria that live in that type water, without frequent water changes.
For example, Oscars, P-bass, and some Geophagine, tend to come down with HITH in hard water in combination with with high nitrates.

I try to maintain my nitrates at no higher than 5ppm, and keep pH stable at 8.2, so I try to do every other day, 30-40% water changes on my 180 gal, and use a heavily planted 125 gal sump as filtration for added nitrate and other non-testable nutrient removal.

There is not a one size fits all water change regime for everyone.
Your tap water, your tank size, your stocking and the geographic evolution of your fish, all contribute

BTW, unless you are using some magic media in them, canister filters do nothing to remove nitrate.

 

[FJB]

"...unless you are using some magic media in them, canister filters do nothing to remove nitrate."
Just about no type of filter will do anything for nitrate. Water changes (and to an extent, heavy plant growth) will.

 

[neutrino]

Agree with much of what Duane said, including, as I preach all the time, "There is not a one size fits all water change regime for everyone. " Over the years, even my own individual tanks might be on different schedules, depending on type of fish, stock levels, etc.

Personally, unless there's some constraining reason to do different, I prefer larger, less frequent water changes. For me it's more convenient and it works well based on my water source, tank and filter setups, and generally light to moderate stocking levels. My nitrates are low, I VERY rarely deal with health issues, and I tend to have long lived fish. In my case my water from the tap is pH in the mid 6s, settles at 7.4 and I leave it at that for all except my Cyphotilapia tank, where I raise KH/pH and add magnesium. (Lake Tanganyika is higher in magnesium than the other major rift lakes and this seems to alleviate the egg impaction issue Cyphotilapia gibberosa can be susceptible to.)

Nitrates/filters/media/substrate/plants, etc. is a somewhat debatable subject and results can vary. I take dogmatic statements on the subject, either way, with a grain of salt.

 

[RD.]

So much in this hobby is not a one size fits all…….

I‘m actually taken back that the OP, who appears to be keeping an Asian aro and black ray in a 180 no less, doesn’t appear to understand the basic fundamentals of water chemistry, and how to manage their tap water and fish. No offense meant to the OP, but wow. That just blows me away. Kudos to at least reaching out and asking.

 

[jjohnwm]

I am happy with one change per week...but it's going to be as close to 100% as I can make it without removing the fish. And I am even happier with a change every 3 or 4 days, and when I do them they won't be much smaller. Done this way, there is no "shock" to the fish because the old water going out is not vastly different than that coming in. Red Cherry shrimp, notorious for being sensitive to changes in water parameters...to the point where shrimp specialists caution against doing large changes...thrive in all my tanks, despite constant water changes.

I worry a bit about shocking fish that haven't been properly kept and are living in tanks that never see a water change...but those are never my fish. I have helped a couple of "torture-aquarists" whose tanks needed major work, and having only a single day to to it, simply removed the fish into a separate bucket with a small amount of the old urine...oops, I mean water...in which they were living and added new water throughout the afternoon, which was spent cleaning the tank and berating the aquarist in question. At the end of the day, the fish in the bucket were in 80% new water; the tank was full of sparkling clean, dechlorinated new water of the proper temperature, and the fish were netted out and plopped in. Great pains were taken not to harm or damage the bacteria in/on the biomedia; those little guys took care of the fish. Then the cycle of neglect could begin again...

I‘m actually taken back that the OP, who appears to be keeping an Asian aro and black ray in a 180 no less, doesn’t appear to understand the basic fundamentals of water chemistry, and how to manage their tap water and fish. No offense meant to the OP, but wow. That just blows me away. Kudos to at least reaching out and asking.

Sadly, it's so common to read about these situations here on MFK that I hardly even notice anymore.

IMHO, the biggest single change in the aquarium hobby over the past few decades is the progression of beginners who know nothing about the maintenance of their fish/biomedia/water. Back then they were neglecting their overcrowded 5-, 10- or 20-gallon tanks. Now the tanks are much bigger, and the fish are larger and much more expensive and exotic...is that progress?

 

[ken31cay]

As mentioned above, water change/tank maintenance will vary.

I normally do 75% weekly wc on both my tanks to maintain nitrate below 10ppm. But I have a new colony of ~year old Frontosa which I'm still feeding a little heavier for a time, so I'm currently doing twice weekly 75% wc.

My tap water is basically RO water with sodium hydroxide and chlorine added, the source is a desalination plant. For my 180gal I change the water very little, but for my 450gal I use a homemade buffer to maintain 8.0 pH, 8KH, 10GH in the tank. I add the buffer solution gradually at intervals as I'm refilling the tank.

When I was into Discus I just added trace elements back to the water but did large daily water changes.

Hope this helps and good luck.

 

[G8zzaj]

So much in this hobby is not a one size fits all…….

I‘m actually taken back that the OP, who appears to be keeping an Asian aro and black ray in a 180 no less, doesn’t appear to understand the basic fundamentals of water chemistry, and how to manage their tap water and fish. No offense meant to the OP, but wow. That just blows me away. Kudos to at least reaching out and asking.

No offense taken, here to learn.

Could You elaborate and help me understand what I’m missing on basic water chemistry and managing tap water and fish?

If the tap water is regarding my question on prime, then my concern was dosing a full water volume every day and if that would overdose, I know to
Does the full water volume each water change but never done daily so didn’t know if this was still the dosage to follow.