salinity issue

spawn · #1 09-17-2011, 04:16 PM

Over the last 5-6 weeks the sal. level in my tank has started to climb on a weekly basis from .026-.028 by weeks end. I think it is due to the amounts of Ca which is dosed at 253ml per day & the Alk which is dosed at 184 ml per day into 55gal GWV. The thing of it is My Ca levels have been on decline for at least the same time period maintaining only 360-380 alk is quite steady @ 7.6-7.8. With dosing these amounts, I'm positive the dosing amounts are exceeding the top off amount causing the increase in the level of sal. Does anyone have any suggestions on what to do about this?

kien · #2 09-17-2011, 04:43 PM

Do yo have an auto top off or do rely souly on your dosing to top up your evaporation? Are you dosing two part?

spawn · #3 09-17-2011, 05:21 PM

I have tunze ATO, & use a profilux for dosing of BRS two part. Is it possible that salt creep is aiding in the up swing? I try to keep it as clean as possible...

daniella3d · #4 09-17-2011, 08:57 PM

What water are you using to do your dosing? if it is done with RO water then the only element added when dosing should be calcium and alkalinity, not salt.

I dose 100ml per day of both calcium and alkalinity and my salinité does not rise at all. I have a top off system with RO water and the water I use for my Bulk Reef Supply 3 parts dosing is also RO pure water.

My salinity stay exactly the same, even after 6 months of dosing daily.

How can dosing calcium and alkalinity in pure RO water cause an increase in salinity? Salt creep usually does the opposite and make you lose salinity over time.

Also what are you using to mesure your salinity? Is it possible that your instrument is going out of wack? Some refractometer have temperature compensation but some don't, so if you are now testing at a different temperature or if your refractometer is not well calibrated, it could give you false result.

I am also surprised that you have to dose so much calcium with the BRS 2 parts in a 55 gallons...how many clam or sps do you have? That seem high.

Quote:

Originally Posted by spawn

Over the last 5-6 weeks the sal. level in my tank has started to climb on a weekly basis from .026-.028 by weeks end. I think it is due to the amounts of Ca which is dosed at 253ml per day & the Alk which is dosed at 184 ml per day into 55gal GWV. The thing of it is My Ca levels have been on decline for at least the same time period maintaining only 360-380 alk is quite steady @ 7.6-7.8. With dosing these amounts, I'm positive the dosing amounts are exceeding the top off amount causing the increase in the level of sal. Does anyone have any suggestions on what to do about this?

George · #5 09-17-2011, 09:30 PM

Dosing 2 parts in high concentration can and will increase salinity. part 1 has about 37,000 ppm calcium (calcium chloride) and part 2 has about 5,300 dkH alkalinity (sodium bicarbonate) per RHF recipe 1. Chloride and sodium are major parts of sea salts as the following image shows.
I think you over dose both parts. Per Randy, he suggests starting dosage of 1mL/gallon of each part in a heavy demand (SPS dominated) tank. Try to dose at 0.5mL/g and slowly increase from there. Measure calcium and alkalinity along the way.

spawn · #6 09-17-2011, 10:20 PM

Quote:

Originally Posted by daniella3d

What water are you using to do your dosing? if it is done with RO water then the only element added when dosing should be calcium and alkalinity, not salt.

I dose 100ml per day of both calcium and alkalinity and my salinité does not rise at all. I have a top off system with RO water and the water I use for my Bulk Reef Supply 3 parts dosing is also RO pure water.

My salinity stay exactly the same, even after 6 months of dosing daily.

How can dosing calcium and alkalinity in pure RO water cause an increase in salinity? Salt creep usually does the opposite and make you lose salinity over time.

Also what are you using to mesure your salinity? Is it possible that your instrument is going out of wack? Some refractometer have temperature compensation but some don't, so if you are now testing at a different temperature or if your refractometer is not well calibrated, it could give you false result.

I am also surprised that you have to dose so much calcium with the BRS 2 parts in a 55 gallons...how many clam or sps do you have? That seem high.

I'm surprised as well, but here is a FTS to help show how much sps & 2 clams slightly larger than a large fist, are in the tank. As for the 2 part contributing to increased sal. Refer to George's pic. The levels have all been stable with this dosing until only recently & there is no signs of precip in the sandbed, on heaters, or pumps? I can only assume that it is being consumed by the corals, even if I adjust levels mid week by supplemental dosing they fall again by weeksend?

spawn · #7 09-17-2011, 10:30 PM

[quote=George;636797]Dosing 2 parts in high concentration can and will increase salinity. part 1 has about 37,000 ppm calcium (calcium chloride) and part 2 has about 5,300 dkH alkalinity (sodium bicarbonate) per RHF recipe 1. Chloride and sodium are major parts of sea salts as the following image shows.
I think you over dose both parts. Per Randy, he suggests starting dosage of 1mL/gallon of each part in a heavy demand (SPS dominated) tank. Try to dose at 0.5mL/g and slowly increase from there. Measure calcium and alkalinity along the way.]

I feel that i am over dosing too, but only in relation to the amount of fresh water that is being added by the ATO, I think the amounts of the 2 part are off setting the amount that the ATO would add if less of the two part were used. But these amounts have seemed to have been accurate to maintain levels of 420 & 7.5 which are what I aim for, as the system is ulns.
Is it worth the risk to knockback the dosed level of CA to match the level of Alk dosed correct the level of CA in the tank water & see what happens? In order to do this I would also have to do at least a 20% WC prior to correcting the levels in order to drop the salinity. Those are gonna be some pretty big swings, & then I personally feel the Ca is likely to take a dive.

daniella3d · #8 09-18-2011, 12:16 AM

wow, very lovely tank! I thought you must have such tank if you use so much calcium.

Quote:

Originally Posted by spawn

I'm surprised as well, but here is a FTS to help show how much sps & 2 clams slightly larger than a large fist, are in the

spawn · #9 09-18-2011, 01:59 AM

Thanks Danielle, but I still think the issue of increasing sal. is due to too much CA & not enough top off / ro. water going in. I've seen pics of your tank, its awesome as well, & if your only dosing in @ 100 ml per day, that's a safer ratio than mine based on the size of setups & size of corals....

daniella3d · #10 09-18-2011, 04:44 AM

Thanks

I don't have a many SPS as you do though...far from that.

I don't know what to say, I have the opposite problem with salinity always getting lower due to salt creep and skimming, even if I dose 100ml of both per day.

Quote:

Originally Posted by spawn

Thanks Danielle, but I still think the issue of increasing sal. is due to too much CA & not enough top off / ro. water going in. I've seen pics of your tank, its awesome as well, & if your only dosing in @ 100 ml per day, that's a safer ratio than mine based on the size of setups & size of corals....