Top Off Water with a 1/2 or diluted salt Mixture.

[Pawlu]

I fully understand that salt does not evaporate, however I have been closely watching my gravity with every fresh water top up and notice that by the end of the week my gravity drops by about 1 to 2 degrees. In my case 1.026 down to 1.024. This is happening on a new 38 Gallon Innovative marine system that has been running for 3 weeks now. I have a marker that shows me the exact level of the water and I have been topping up daily with fresh RO water (Currently very dry in the house and evaporation in winter is high). However a certain level of salt is also being lost and is reflected in the drop of salinity. I am starting to wonder if the top off should not be pure RO water but instead a diluted salt mixture.

Has anybody experimented with this? An auto top off system is on my list but until then I need to find a more stable way of keeping salinity levels fluctuation by no more then 1 degree.

Thanks.

 

[SubRosa]

Protein skimming and salt creep account for the drop. If you can skim a bit drier you might lessen the drop. Imo using top off to adjust salinity is a bad idea, because if you use water changes to make your adjustments, you're more likely to do the water changes.

 

[Pawlu]

Thank you SubRosa, can you explain what Skimming Dryer means? Is it basically reducing the air to water agitation?

 

[SubRosa]

It means that instead of emptying your skimmer cup by pouring it, you need to use a tiny shovel to get the crap out! Don't seek instant gratification from your protein skimmer. Let it run a day at a very low setting that produces no foam in the cup. Turn it up a tiny bit, let it run another day and see what happens. Repeat until it just starts producing stuff in the cup. That is dry skimming. You'll see a much darker, thicker crud, often as a thick build up on the inside of the upper part of the skimmer neck.

 

[Pawlu]

Ok thanks I will start very low and work my way up on the dial.

 

[BigAl07]

One thing that caught my eye was when you said:

I have a marker that shows me the exact level of the water

This sounds like you're most likely using a "Swing Arm Hydrometer" (SAH). The sooner you start using a refractometer the sooner you can be accurate with your SG readings. Swing Arm Hydrometers (SAH) are notoriously unreliable and can easily be held responisible for several tank melt-downs. If the SAH isn't carefully cleaned and maintained after EVERY use and used in very precise manner deviations can occur.

If your tank is losing salt that quickly either you have a testing/monitoring issue (SAH) or you have something else happening that needs to be addressed. Even on tanks with VERY high evaporation (sometimes we use excessive evaporation as a secondary means to cool the tank) you shouldn't be seeing a drop like that.

Yes it's true some salt and other "elements" do leave the water column through evaporation (evidence by prematurely rusty HVAC in homes with larger tanks over a period of time) it should be negligible at the most.

Regardless of the problem at hand upgrading to a refractometer (usually less than $50 at many retailers) is a great idea and IMHO should be part of every new SW enthusiasts beginner kit. Why not spend the $$$ that would have been a SAH and get a refractometer to do it right to begin with???? Money saved in the long run from how I see it

 

[steved13]

+1 on dry skimming, and a refractometer.

Be careful using water changes to adjust salinity, that you don't adjust too fast. If you're going to use water changes, try overfilling the tank slightly on the refill, and as the water evaporates to the proper level the salinity will rise gradually.

 

[Pawlu]

One thing that caught my eye was when you said:


This sounds like you're most likely using a "Swing Arm Hydrometer" (SAH). The sooner you start using a refractometer the sooner you can be accurate with your SG readings.

Hi Big Als, no I don't use a Swing Arm Hydrometer, I do in fact use a refractometer, by marker/level I was referring to a place mark in the overflow that shows how much has evaporated. Its simply a water level marker. How often do refractometers need to be calibrated, I have had mine now for about 4 months?

 

[BigAl07]

Thanks for the clarification.

I try (key word being TRY) to calibrate mine when I change the batteries in my smoke detectors (Spring Forward/Fall back time change). Actually that's when I have tested my calibration but I've never needed to adjust mine... to date it's been rock solid.

 

[Pawlu]

Thanks for the info, and while we are on the topic of calibration, I have a RKL (Reef Keeper Light) controller with both a PH and Temp probe, the PH probe was calibrated with the stock calibration fluids. According to Digital Aquatics the PH probe should be calibrated every month, do you know if the calibration liquids can be re-used if kept in a sealed container, or do I need to purchase fresh packs every time?

Thanks

 

[BigAl07]

So long as they are sealed and not contaminated I have had no problem using them over and over. I tell most customers that I would replace it annually.

 

[Pawlu]

Great thanks!