people with auto water changers

I have been want to buy a DOS for this reason. It's just hard to part with the cash. But it would be way easier. I could see dosing a lot less doing daily water changes especially if salt mix has elevated levels of calcium, alkalinity, and magnesium.
Donny what's that's salt your using mix up to on a fresh batch for those parameters at 1.025-1.026 salinity?

 

Cool. Thanks. I run salinity and if I mix with a pump for a few days the alkalinity precipitates out. Mixes to around 9 dhk ends up at a little under 7 mixed to long.

 

I was once told standing salt waters alk will drop without an airstone in it if left too long. Never had an issue with this as I don't leave mine very long before using it...and also don't know the validity of it...but may be worth looking into.

 

I really like my DOS for AWC. You will still have to dose though. The amount of calcium and alk from a 1-2% WC is not all that significant when most reef tanks drop 1-3+ DKH per day. Unless someone is doing over 50% waterchanges per day.

 

Some salts that are really high in alk and calcium can precipitate out just over time as they have considerably more calcium and alk than natural salt water and are not stable for long periods. Red Sea Coral Pro is notorious for this and from the manufacturer "Do not mix more than 4 hours". Also when running an pump as the impeller can get pretty hot and drop some out of solution.

 

Well I have read that if Salinity is heated or over mixed that it will happen. They recommend for that salt to only mix for 2 hours and it's ready for use.
I almost always have 30 gallons mixed and ready to go. I have been using this salt for about 3 years. It leaves some residue in mixing container. I usually never check parameters on newly mixed salt except for salinity. But I am running a smaller tank now along with my sps system and noticed alkalinity fluctuations after water changes. I never noticed on my bigger system. So now I just add some 2 part if needed before water change.
If I can find a salt that mixes close to what my parameters run I will change after I run out of Salinity.
My tank parameters run about
Alkalinity 8.5
Calcium 420
Magnesium 1400
Ph 8.3
At 1.026

 

When I do get the Dos probably change around 3-4 gallons a day. I currently do 1 20 gallon change weekly. When I have more time I was doing 2 10 gallons a week.
I just want to be able to mix a full barrel of water and be good for a week or 2 before I need to refill and not worry about alkalinity and calcium precipitating out and have to add more to my daily dose to compensate.

 

I switched to Instant Ocean when starting AWC, no vitamins like reef crystals or other organics that will either go bad or otherwise be altered in storage and calcium closer to NSW (I think they target 400ppm CA, 1300 mg and around 10dkh). No issues with it sitting for me. I don't stir it after the initial mixing and it keeps just fine for a month.

Back to the AWC and dosing. Even a 10% waterchange with 11dkh water will only raise the alk by around 0.2dkh if your tank is at 9dkh to start with - so even a 10% daily WC is only around dosing 0.2dkh in that setup, not enough to matter for most of us.

 

I just like the parameters to be close to what I usually run in case I need to do a large water change for some reason.
I never noticed or even tested at all when doing water change on approx 200 gallon system. Like you said it will barely change if at all but on a 40 gallon system I do 5 gallons a couple times a month and I do notice some difference. I just add some 2 part.

I guess only changing a few gallons a day will pretty much go unnoticed.

 

http://www.reef2reef.com/threads/mixing-salt-water-for-too-long.207262/
Here's a good link about it in r2r

 

There is also one on Aqu Vitro Salinity salt. Basically says same thing.

Sorry to get off topic of dosing.

 

I keep a bottle of muratic acid around so if I need to do a really large WC I can match the new water to whatever my tank is currently at since my alk drifts a bit month to month. Few ML drops the alk well with no other effects. Might be 7 this month and 8 next month if the dosing isn't right on. I don't adjust the dosing until I get to either 7 or 9dkh (target of 8)- if that is slow over a month or two that is.

 

I have always mixed up 50 gallons at a time. I have a 65 gallon water storage for my salt so when it gets below 10 gallons I just fill tank with Ro/Di and pour 50 gallon salt mix. I will check mine and see.