Numbers good, cal low low

[tony1970]

ok well we finished the 180, from a 90 to a 180 upgrade,(since may2008) and things look good, numbers in line ect. but we have serious problems with low calcium

We been using b ionic for over ayear, on the 90 it worked great.

The 180 we were running around 350 cal with sal 1.025 mag 1350-1400 alk around 9.5-10.5 dkh

So we increased the b inoic dose, and in 3 days the alk didnt really move, but the calcium dropped to 320.

Now usually this method works no problem, so im kind of confused as to what could be slwoing down the calcium reaction in the tank, especially after we increased.

*edit (helping my friend who built the 180)

just redid the test a few more times, mag level is 1260, i know thats low and causes cal levels to drop, but last week we had same reading and dosed 800ML in a week of magnesim (b ionic)

Now the test still showing same levels, i thought this was alot of magnesim and should of bumped it at least 60-80 ppm.

 

[Billybeau1]

Well, first off, mag at 1260 is not too bad. NSW is at 1290 and with the test noise in magnesium kits, you are in the ballpark.

What salt mix did you use to start the 180 ?

 

[tony1970]

Doing more test**
We have a auto top off system for plain r/o if salinity rises above 1.025 (50 cond on the probe)or evaporation

We also have a automatic water changer set up, we drain 1.5 gals of tank water every 24hrs and its replaced by a salt mix.

Tested salt mix (instant ocean reef crystals), and we keep salinity high 1.040 in salt mix.

readings on the salt mix are, 500 cal, 1500 ppm mag, 13.8 dkh,
so 1.5 gals of this mix is changed per day, with the addition of bionic dose of 12 ML part 1 &2 per 24 hrs.

Tank was started with IO reef crystals, and about 50 gals of the 90 tank water transfered and the first month readings were 420-450 cal, its the past month or 6 weeks its been bouncing in the 300 range.

Just wondering if we shoudl continue adding more magnesim to bring it up more, or just leave mag levels alone.

I know in the 90 gal wekeept a mag level of 1350-1375wih cal levels of 450 or so (which was high end and we brought it down)

 

[Billybeau1]

For magnesium, anything between 1250 and 1350 is fine.

As far as your replacement water, I would not make it 1.040

I would make the replacement water the same as the tank which is hopefully around 1.026

Salt does not evaporate. Water does. You will soon find your tank at a much higher s.g. than you want.

Daily automated water changes are about the best you can get. I know that's what Randy does.

1.5 gallons daily in a 180 gal tank is about 10.5 gallons a week or 21 gallons bi-weekly.

I would think about increasing the amount of the daily change.

 

[tony1970]

yeah that was one of my concerns with the replacement water, salt doesnt leave tank unless you take it out (very little forms on surfaces that would cause any sufficent change in salinity) we do currently run tank at 1.025, back oh 15 yrs ago, i use to run mine at like 1.024 .

but now people running at 1.026? (needs to go test his water in ocean)

But anyways would a change in salinity to 1.026 from 1.025 move calcium and magnesim that much?

 

[Billybeau1]

Well, depends on the amount of calcium in the salt mix.

Lets say IO has 350 at 1.026

350 div by 26 is is about 13.5 so it may make a difference of about that which is difficult to pin down with the test kits we use.

Conversely, Oceanic runs around 580 at 1.026 so 580 div by 26 is a little over 22 ppm. You may catch that with our calcium kits.

Just think of people who are 3 points off on their specific gravity due to testing error.

This could mean as much as a 67 ppm difference in the calcium level added to the tank.

 

[tony1970]

ok well thanks for your help, were also looking at the possiblity the auto changer could be turning the r/o instead of the salt mix when doing water replacement, im goiing to hhave him set it up so this cant occur, and hope he can set it so only if the salinity rises above 1.026 that it turns r/o on only, for safety reasons.

we think this is the most logical answer to such a drastic drop in calcium and magensim. its possible the cond. probe is picking up this dense salt of 1.040 and turning r/o instead of the mix, while at same time throwing away good water and not replacing it properly.

So i have him set salt mix to 1.025 and to stop the r/o from kicking in from the comd probe. we test and see, will post results.

Thanks again

 

[Billybeau1]

:thumbsup: Good luck and keep us posted.