Dumb Water Change Question

specialk · Nov 15, 2016

Stupid question possibly ..

But just started on 1st dosing program and getting parameters stable and in check. I was doing and still planning on doing water changes (at 10% - 15% water change of a 145 gal system) ...

But when doing the water change (also of note I user Instant Ocean Reef Crystals) do I want to stop dosing as the new salt water will take my parameters up possibly above what I am keeping them at?

For example, I keep my alk steady at 8.9, when I do the water change won't it raise a bit due to the new salt (raise it to say ... 11) and thus cause swings in the water? (and obviously we want things steady and stable ... not moving all over the place)

Just wondering how the water change will effect the swings to my key water factors like alk, calcium and mag.

Ocelaris · Nov 15, 2016

I don't know the exact answer, but the way I think about it is that alkalinity is a number of molecules. So for example you have 30 gallons of 11 dkh water, and your system is 145-30 gallons or 115, at 8.9, that's roughly 26% so you may go up .26x2dkh or .5 dkh. Rough math, but that's my guesstimate. Probably more complicated, but that's my logic.

specialk · Nov 15, 2016

Ocelaris said:
I don't know the exact answer, but the way I think about it is that alkalinity is a number of molecules. So for example you have 30 gallons of 11 dkh water, and your system is 145-30 gallons or 115, at 8.9, that's roughly 26% so you may go up .26x2dkh or .5 dkh. Rough math, but that's my guesstimate. Probably more complicated, but that's my logic.

Do I just continue to dose as usual and not stop or paise anything...? or should I test and start dosing when #s come down to where they were?

Ocelaris · Nov 15, 2016

I don't want to steer you down the wrong path, let's wait for an expert to chime in, but... .

How much do you dose to compensate for alkalinity use each day? If you're not dosing more than a half dkh, then you'd probably be fine. But if you're dosing a full dkh, then you'd be over the reccomended 1 dkh change per day reccomendation.

Dramad1 · Nov 15, 2016

When I do a wc, I don't dose that day and I skip the day after dosing and then resume the following day and test at the end of the week. Seems to stay pretty level.
Forgot to mention, I'm using rscp, it has some higher levels. I just ordered a new box of fritz pro rpm and plan on giving this a shot. Mixes lower than rscp with and alk of like 8.6 or so. I'll have to test daily again and probably change my dosing accordingly

justingraham · Nov 15, 2016

I would change ur salt to a salt that is more in line with the parameters u are trying to achieve. This way when u do a water change it's replacing the same dkh calcium and mag . And yes I would not dose anything until ur numbers come back down. How much dkh calcium and mag are u losing a day?

specialk · Nov 15, 2016

Dramad1 said:
When I do a wc, I don't dose that day and I skip the day after dosing and then resume the following day and test at the end of the week. Seems to stay pretty level.
Forgot to mention, I'm using rscp, it has some higher levels. I just ordered a new box of fritz pro rpm and plan on giving this a shot. Mixes lower than rscp with and alk of like 8.6 or so. I'll have to test daily again and probably change my dosing accordingly

Im gonna look into that stuff. I keep my alk right about 8.6!

Dramad1 · Nov 15, 2016

Yeah rscp is a Lil Higher in alk, I run right at 8.6 for alk and 420 ca1380 mag. When I mix the rscp it mixes I. The high 11's for alk, this is why I skip the day of and after dosing post wc.
I feel like I will be able to maintain a more stable alk using fritz which mixes at 8.6 for alk

specialk · Nov 15, 2016

justingraham said:
I would change ur salt to a salt that is more in line with the parameters u are trying to achieve. This way when u do a water change it's replacing the same dkh calcium and mag . And yes I would not dose anything until ur numbers come back down. How much dkh calcium and mag are u losing a day?

Im currently using and dosing about 110 ml of alk a day.

Also currently waiting for calcium and mag to come down as I had a bad batch of salt before (called IO and they said this does happen from time to time) so had high mag and calcium. ..waiting for them to gradually get back to the #s I want

Sabellafella · Nov 15, 2016

specialk said:
Im currently using and dosing about 110 ml of alk a day.

Also currently waiting for calcium and mag to come down as I had a bad batch of salt before (called IO and they said this does happen from time to time) so had high mag and calcium. ..waiting for them to gradually get back to the #s I want

Do you use a dosing pump or dose by hand? And What 2 part are you using?

justingraham · Nov 15, 2016

It shouldn't just happen. Man I would be mad at that salt company. If u messed up at work and u told ur boss hey it just happens what would happen?
I use Red Sea blue can it mixes at I believe 8.3 and I have no complaints

specialk · Nov 15, 2016

Sabellafella said:
Do you use a dosing pump or dose by hand? And What 2 part are you using?

Dosing pump. Buble mag. Dose BRS

specialk · Nov 15, 2016

justingraham said:
It shouldn't just happen. Man I would be mad at that salt company. If u messed up at work and u told ur boss hey it just happens what would happen?
I use Red Sea blue can it mixes at I believe 8.3 and I have no complaints

Lol...yah I was ticked! They sent me an entirely new 200 gal box but yah I was NOT pleased

hyhy · Nov 15, 2016

Some people use the cheap IO salt which has low ALK like 9 or less. They dose to make up for the consumption of their corals....

Ocelaris · Nov 16, 2016

Even a high alk salt isn't going to drastically change your alk unless you're doing a 50% water change. See math from before. I think the key is to stick with whatever you have been using and the differences will be within tolerances. The margin on salt is so low I'm actually pleased to hear they compensated you. I do io or reef crystals whatever the store has and consider it a gift if there's more alk, but I can see where people would worry.

What's your mixing procedure? I just say because a vigorous mix and aerate may help precipitate out stuff at the beginning. I use an old skimmer pump with air and a pan world pump for an hour or so, then switch back to just the skimmer for 5 minutes every half hour.

specialk · Nov 16, 2016

hyhy said:
Some people use the cheap IO salt which has low ALK like 9 or less. They dose to make up for the consumption of their corals....

Thats not a bad idea .. I may do that after I use up this 200 gal box of reef crystals that I have! Would def save a couple bucks!

specialk · Nov 16, 2016

Ocelaris said:
Even a high alk salt isn't going to drastically change your alk unless you're doing a 50% water change. See math from before. I think the key is to stick with whatever you have been using and the differences will be within tolerances. The margin on salt is so low I'm actually pleased to hear they compensated you. I do io or reef crystals whatever the store has and consider it a gift if there's more alk, but I can see where people would worry.

What's your mixing procedure? I just say because a vigorous mix and aerate may help precipitate out stuff at the beginning. I use an old skimmer pump with air and a pan world pump for an hour or so, then switch back to just the skimmer for 5 minutes every half hour.

You use the regular IO and not the reef crystals .. so I am assuming you fall into the group that hyhy mentioned, and just use the regular stuff and dose the rest of the key elements?

And my mixing procedure is I pretty much use an 18 gal tote tub, add the mix to the RO/di water and use and old skimmer pump submerged in the tote to let the salt mix.

Ocelaris · Nov 16, 2016

All salts have all the elements necessary, there are no elements missing. Not sure what you mean camp that doses other elements. Regular water changes provide all necessary elements and we're just adjusting alk, Calc and magnesium.

Some salts add stuff to differentiate themselves like organic material, but I don't think that has any value. You can toss in any magic elixir you want afterwards, but salts are basically all the same. Listen to reefthreards podcast about salt with Craig bingman.

tripdad · Nov 16, 2016

You should test your new ASW and adjust the params to match your existing, raise or lower Alk, cal, mag to match, then do water change. An explanation on how to do any or all is available in Randy's chemistry articles. Also match the temp but assume most know that already.