How big of a water change should I do?

[nick654377]

Just did a water change Monday. I check parameters every other day and a few concerns.

calcium is rapidly increasing……

alk was 8.5 and I dosed 3 tbsp of baking soda to being it up to 9-9.5 on a 65 gallon and it shot up to 12.x

ammonia spike is due to a nem running away and hiding then dying.

how large of a water change should I perform with these numbers? I do not dose anything yet and generally do a 15-20g change once a week.

 

[Unitylover]

at most, do a 50% water change because more than that could wreck havoc on the bacteria, and the levels aren't to high, they're high tho

 

[nick654377]

at most, do a 50% water change because more than that could wreck havoc on the bacteria, and the levels aren't to high, they're high tho

I was thinking 20-25 gallons as that is about half of my tank. It’s a 65 with a decent amount of rock.

how do you guys combat having monti glued to the top rock? If I do more than 15 gallons they are exposed for a minute. Maybe 5-10 minutes max.

 

[Unitylover]

maybe do 2 10 gal water changes, so it wont be exposed.

 

[Randy Holmes-Farley]

Why do you want to do any water change? Just to lower alk from the baking soda overdose?

Calcium is not rising on its own. it is test error or a salinity rise.

Stop dosing anything. (you say you dose nothing but obviously dosed baking soda)

 

[Unitylover]

Why do you want to do any water change? Just to lower alk from the baking soda overdose?

Calcium is not rising on its own. it is test error or a salinity rise.

Stop dosing anything. (you say you dose nothing but obviously dosed baking soda)

He also has ammonia levels tho.

 

[Randy Holmes-Farley]

He also has ammonia levels tho.

I suspect the ammonia may be test error. If he has removed the anemone, it would rapidly drop if real. Some kits often show that level when none is there. API often does that, for example.

 

[Unitylover]

I suspect the ammonia may be test error. If he has removed the anemone, it would rapidly drop if real. Some kits often show that level when none is there. API often does that, for example.

good point, I cant argue with that lol

 

[muzikalmatt]

Is there a particular reason you were dosing baking soda? An alkalinity of 8.5 is perfectly fine (typically what I shoot for), so unless you're purposefully targeting a higher alkalinity level I'm not sure why would need to dose. If you are planning to dose, you don't want to jump more than a single dKH in a 24 hour period.

Also, what salt mix are you using? Have you looked at the levels of your freshly mixed saltwater. Certain salts have elevated calcium and alkalinity levels which could be contributing to your elevated levels. (Reef Crystals for example has a calcium of 490-500ish.)

Honestly though, none of your levels are concerning enough to necessitate an immediate large water change. You can allow the calcium and alkalinity levels to come down naturally, and as @Randy Holmes-Farley pointed out, the ammonia reading is probably a false positive. Even if that's not the case, 0.25 ppm is not going to kill anything yet. Once you hit 0.5 ppm or higher you should start to worry, so it might be worth checking ammonia again to see where your levels are at and if they're continuing to rise.

Finally, you can absolutely do larger than 50% water changes. It's not going to harm your bacteria. Some people do 90-100% water changes periodically. While it's not practical for larger tanks, it can be extremely useful for nanos. If you're doing a large water change though (say 25% or more), you want to match the key parameters (temperature, salinity, and alkalinity) to prevent from shocking your corals.

Again though, I don't see anything in your levels alarming enough to necessitate an immediate water change. Your nitrates and phosphates are almost perfectly balanced with the redfield ratio, which is what you want typically. I run my tank around those levels (between 10-20ppm nitrates and 0.10-0.20ppm phosphates).

 

[nick654377]

Is there a particular reason you were dosing baking soda? An alkalinity of 8.5 is perfectly fine (typically what I shoot for), so unless you're purposefully targeting a higher alkalinity level I'm not sure why would need to dose. If you are planning to dose, you don't want to jump more than a single dKH in a 24 hour period.

Also, what salt mix are you using? Have you looked at the levels of your freshly mixed saltwater. Certain salts have elevated calcium and alkalinity levels which could be contributing to your elevated levels. (Reef Crystals for example has a calcium of 490-500ish.)

Honestly though, none of your levels are concerning enough to necessitate an immediate large water change. You can allow the calcium and alkalinity levels to come down naturally, and as @Randy Holmes-Farley pointed out, the ammonia reading is probably a false positive. Even if that's not the case, 0.25 ppm is not going to kill anything yet. Once you hit 0.5 ppm or higher you should start to worry, so it might be worth checking ammonia again to see where your levels are at and if they're continuing to rise.

Finally, you can absolutely do larger than 50% water changes. It's not going to harm your bacteria. Some people do 90-100% water changes periodically. While it's not practical for larger tanks, it can be extremely useful for nanos. If you're doing a large water change though (say 25% or more), you want to match the key parameters (temperature, salinity, and alkalinity) to prevent from shocking your corals.

Again though, I don't see anything in your levels alarming enough to necessitate an immediate water change. Your nitrates and phosphates are almost perfectly balanced with the redfield ratio, which is what you want typically. I run my tank around those levels (between 10-20ppm nitrates and 0.10-0.20ppm phosphates).

it was not test error. I test every other day and am very ocd about my testing. The nem has not been found. It was a small 2-3 inch one and it is under multiple rocks that I honestly do not feel like breaking apart to look for it. I am sure my snails, pepermint shrimp, and blood shrimp have ate at it by now. I did do a 15 gal water change and will check again tomorrow.

and again 1tablespoon of baking soda raises dkh 1.0ppm per 10 gallons. I have a 65 gal and only put 3 tablespoons in to bring it up 0.5ppm but it did not work. I like keeping my dkh around 9.1-9.5 personally so once it drops I will maintain it with redsea that just came in.

 

[Randy Holmes-Farley]

and again 1tablespoon of baking soda raises dkh 1.0ppm per 10 gallons. I have a 65 gal and only put 3 tablespoons in to bring it up 0.5ppm but it did not work. I like keeping my dkh around 9.1-9.5 personally so once it drops I will maintain it with redsea that just came in.

That is definitely not correct if you mean dry baking soda as opposed to a liquid solution. Where did you get that from?

3 tablespoons of baking soda in 65 gallons boosts alk by 5.7 dKH

Reef Chemistry Calculator

As to the testing, when you say ammonia is not test error, how do you know? A bad test does not always imply user error.

 

[nejohnson]

and again 1tablespoon of baking soda raises dkh 1.0ppm per 10 gallons. I have a 65 gal and only put 3 tablespoons in to bring it up 0.5ppm but it did not work. I like keeping my dkh around 9.1-9.5 personally so once it drops I will maintain it with redsea that just came in.

That is definitely not correct if you mean dry baking soda as opposed to a liquid solution. Where did you get that from?

3 tablespoons of baking soda in 65 gallons boosts alk by 5.7 dKH

Reef Chemistry Calculator

@Randy Holmes-Farley Sorry to dig up a month old thread, but I'm working on fixing an alk overdose, came across this discussion, and I think it's because of this same bad information stemming from a quick Google search. This is the Google result:

In my case, I did 2 tbsp for about 25 gallons of water volume, added over ~14 hours. My tank shot from 6.1dKH to 17.2dKH. I feel like an idiot now for acting on a single Google result without proper research first.

 

[Randy Holmes-Farley]

Fortunately, that incorrect post is no longer the first hit on google for that search.