Water. Make vs Buy? RODI etc?

FireViper · 02/22/2019, 05:32 PM

Curious as to the decision making process for salt water and for fresh water top offs. First of all, were in the San Francisco Bay Area, so salt water is fairly cheap, about a dollar a gallon. Still, the math works out in favor of DIY water, as RODI is about half the price of sea water. Does real ocean water have any benefits? Apparently the sea water at the LFS comes is collected locally from the ocean and is run through a filter system.

We could always make our own RODI so it be cheaper still, but our tap water has a pH of around 9.3. Will a RODI process lower that? I assume the RODI process will remove the chlorine, fluoride, resolve the hardness, etc., correct?

Thanks!

Uncle99 · 02/22/2019, 05:53 PM

Quote:

Originally Posted by FireViper

Curious as to the decision making process for salt water and for fresh water top offs. First of all, were in the San Francisco Bay Area, so salt water is fairly cheap, about a dollar a gallon. Still, the math works out in favor of DIY water, as RODI is about half the price of sea water. Does real ocean water have any benefits? Apparently the sea water at the LFS comes is collected locally from the ocean and is run through a filter system.

We could always make our own RODI so it be cheaper still, but our tap water has a pH of around 9.3. Will a RODI process lower that? I assume the RODI process will remove the chlorine, fluoride, resolve the hardness, etc., correct?

Thanks!

I would not trust sea water as I don't know what is in it. In the ocean, the water is big it dilutes a billion times over but in a reef tank, could be high levels of anything.

RODI removes everything, (0 TDS) is always best to make yourself as it is a critical component. Be a master of making and deploying water and success skyrockets.

FireViper · 02/22/2019, 06:56 PM

Quote:

Originally Posted by Uncle99

I would not trust sea water as I don't know what is in it. In the ocean, the water is big it dilutes a billion times over but in a reef tank, could be high levels of anything.

RODI removes everything, (0 TDS) is always best to make yourself as it is a critical component. Be a master of making and deploying water and success skyrockets.

Thanks. Will RODI "fix" pH in tap as well? Ours is borderline dangerously high for humans at 9.3.

dkeller_nc · 02/22/2019, 07:03 PM

Yes. There are two aspects to pH - both the pH itself, and how much buffering capacity the water has. A properly functioning RODI system should in theory remove absolutely everything that's dissolved in the water, and the end result of that should be water with zero buffering capacity and a pH of about 6.8 (because some carbon dioxide will dissolve in it, it won't be precisely 7.0).

Even if you measured the pH of water coming from a RODI system at a pH of 9.0 because of some residual leak-by of the source water, the very low buffering capacity of that water would mean that dissolving a teaspoon of saltmix in a large bucket would still give you a pH of 8.3, much less actually making artificial seawater up to a specific gravity of 1.026.

02/22/2019, 05:32 PM	#1
FireViper Registered Member Join Date: Jan 2019 Location: San Francisco Bay Area Posts: 120	Water. Make vs Buy? RODI etc? Curious as to the decision making process for salt water and for fresh water top offs. First of all, were in the San Francisco Bay Area, so salt water is fairly cheap, about a dollar a gallon. Still, the math works out in favor of DIY water, as RODI is about half the price of sea water. Does real ocean water have any benefits? Apparently the sea water at the LFS comes is collected locally from the ocean and is run through a filter system. We could always make our own RODI so it be cheaper still, but our tap water has a pH of around 9.3. Will a RODI process lower that? I assume the RODI process will remove the chlorine, fluoride, resolve the hardness, etc., correct? Thanks!

02/22/2019, 07:03 PM	#4
dkeller_nc Registered Member Join Date: Mar 2013 Location: Central NC Posts: 5,062	Yes. There are two aspects to pH - both the pH itself, and how much buffering capacity the water has. A properly functioning RODI system should in theory remove absolutely everything that's dissolved in the water, and the end result of that should be water with zero buffering capacity and a pH of about 6.8 (because some carbon dioxide will dissolve in it, it won't be precisely 7.0). Even if you measured the pH of water coming from a RODI system at a pH of 9.0 because of some residual leak-by of the source water, the very low buffering capacity of that water would mean that dissolving a teaspoon of saltmix in a large bucket would still give you a pH of 8.3, much less actually making artificial seawater up to a specific gravity of 1.026.