SG Raising question

[strandeviper]

I have an open sump on my 150 reef system. Every 3-4 days, I need to add a gallon to top the sump off. I've been using RO water to top my sump off and my SG is raising. It has raised from1.025 to 1.027 in the last 10 days. Im getting concerned about the SG level if it continues to rise. How is RO causing the SG to rise?

 

[fraggleRocks]

If you have a 150 gallon system, and you are only adding 1 gallon evey 3-4 days then I think there is your answer. Not enough evaporated water being replenished.

I have a 90 gallon, with another 40 gallons in my sump. Every week (6 days) I need to add a total 7-10 gallons of RO over time because of evaporation.

The salt in the system will not evaporate, the water will. If you dont replenish all of the water lost to evaporation, they your SG level will creep up on you like that.

Mark your sump on the outside with a sharpie where the full level is and only top off with RO.

If your sump is full already then consider removing saltwater from your overall system and replenishing it with RO water to get the SG level down, if thats what you want to do.

Hope this helps

 

[wrott]

Are you using a refractometer? If not, that is the answer. In a SW tank, if the water level is maintained, the SG could only decrease due to a leak somewhere. It can not increase. (unless you are dosing Tech-M or a bunch of other salt compounds)

 

[strandeviper]

I am not using a refractometer, but im looking into one. I might be getting a lil more evaporation, but not much more. I have no leaks. Ill look at taking some water out when i get more RO water in on Monday. Other then replacing, is there anything else I can do?

 

[wrott]

Nothing else you can do except take a water sample to a LFS that has a refractometer and adjust accordingly (may be even ask to borrow it for 1-2 hrs !!).
A water leak would cause SG to decrease.
What kind of hydrometer do you have? If you have a nice old-school glass, then you're OK if you spin it to get the bubbles off, but it sounds like you have a swing-arm--they are useless in our hobby if you want long-term success.

I've had my SG fluctuate from 1.024 to 1.030 (due to lack of maintaining water level in sump) with no ill effects on any livestock, so really don't worry too much right now. cheers

 

[strandeviper]

i do have the useless swinging arm. I only have snails and hermits right now, my system finished its cycle four days ago and am still making sure the bacteria can handle the waste load. In about a week im going to start adding a few live stock to get it going. Im also looking at a few refractometers. What is a good refractometer to purchase?

 

[wrott]

I've bought 2 differnt brands, both were ~ $50. But for reference, I'd look at:
http://premiumaquatics.com/store/me...ode=PA&Product_Code=REFRACT-HD&Category_Code=
and use the 35ppt standard to check calibration.

 

[tkeracer619]

Don't adjust your water based on a swing arm. Mix the water per instructions on the bag until you can buy a refractometer.