New mix, High Kh, Problem?

[fishystream]

Hello all,

I just made 5 gallons of Instant Ocean saltwater mix. Before adding the mix to the water it tested at 9 Kh, but after adding the mix and letting it sit over night with a pump, now it reads 18 Kh. Any ideas on how to lower the Kh on a saltwater mix? Will it naturally drop over time? if so how long?

Thanks.

[disc1]

Was this made with tap water? If your tap is that high in alkalinity then you will absolutely need to get a RODI. Topping off with that will push your alk through the roof.

How big of a water change are you planning and what is the alk in the tank? Let's see if it is even necessary to bring it down. It can be done by adding a mineral acid but that has a few serious caveats.

[dan1789]

How did you test it before adding it to the water. I don't understand the before and after test.

[fishystream]

Yes it was made with tap water. Is alkalinity and Kh different?
Testing the tap waters Kh resulted in 10 kh. After adding the mix it raised it to 18 kh.

[fishystream]

The current kh in the tank is 10 kh. It's a 2 gallon nano. I always buy my saltwater at the LFS but since in starting an 8 gallon nano I want to give it a shot at making the mix. I know a reverse osmosis system would solve my issue, but is it possible to make with tap when it's kh is at 10 ( tap water)?


Was this made with tap water? If your tap is that high in alkalinity then you will absolutely need to get a RODI. Topping off with that will push your alk through the roof.

How big of a water change are you planning and what is the alk in the tank? Let's see if it is even necessary to bring it down. It can be done by adding a mineral acid but that has a few serious caveats.

[disc1]

I know a reverse osmosis system would solve my issue, but is it possible to make with tap when it's kh is at 10 ( tap water)?

It will be a constant battle to lower the alkalinity. It will have its biggest impact coming from the top off water more than the water changes. That top off adds alk, the water evaporates leaving that alk, and then here comes more top off with even more alk. It is analogous to the SG climbing if you were to top off with saltwater. A one time adjustment with mineral acid like HCl is OK, but if you start doing that every day you are going to create a lot of other issues.

I would say that using tap water that is that hard in your tank is a disastrous idea. No way that is going to work out.

[fishystream]

Would something like a PUR water filter work? When I search for reverse osmosis filtration I get lots of options. Prices vary from $40 to $400. Thanks for the help. Just trying to find a way to do this from home. :)

[disc1]

Would something like a PUR water filter work? When I search for reverse osmosis filtration I get lots of options. Prices vary from $40 to $400. Thanks for the help. Just trying to find a way to do this from home. :)

No, a PUR filter is just a carbon filter. Decent for removing chlorine and taste, but isn't going to remove any of the salts or hardness.

You're going to need a RODI. Believe me when I tell you that just about every "Can I just use this cheap thing" option has been looked over. You're not the first to not want to get a RODI unit. Go to one of the sponsors here, I like BRS myself, and look at the RODI systems. You can get a good one for the $150 to $200 range. To remove that hardness you're going to have to have at least one DI stage. There's really no other way round it if you want to use that water in your tank. Beware of the cheap DI only units. They look like a great deal, but there's a really good reason why all of us don't have one and go for RODI instead. That DI only unit will burn through resin like nobody's business and with water as hard as yours you'll be lucky to make 30 gallons before you burn it up if you don't have an RO stage in front of it.

[bnumair]

I second that. Use rodi water only for this hobby. Right now alk is a problem tomorrow algae will be then after u may or may not be able to grow corals if there are things like copper in water
Rodi will be the best investment u will make for ur tank.
BRS sells good units for this hobby. Dont fall for cheap ebay units which are mostly designed for drinking water.

[bertoni]

Alkalinity and dKH technically are different, but in hobbyist usage, they are the same. I agree that a RO/DI unit is a good investment. You can lower the dKH of the tapwater by adding a mineral acid, such as sulfuric acid, to it, but I wouldn't want to handle hazardous chemicals, and that only fixes the alkalinity part of the problem.

[6060reef]

Yes it was made with tap water.

WHY???? Get an RODI unit from BRS and call it a day!