Reef Calculators

[jduong916]

I've been trying to use the reef calculators to determine how much alkalinity solution needed to boost my ALK by 0.7 DKH. I have a 120 with a forty gallon breeder and I assumed about 135 gallons total after estimating rock volume and actual volume used in the sump. I use Randy's 2 part and the calculators say I need to add 77 ml. I added 50 ml and waited an hour to test. The results went from 9.0 to 10.8 DKH. This seems to happen every time I try to correct my values. Could this be the test kits? Could it be my alk mix? When I dose normally about 40 ml a day the results seem to stay consistent or slowly lower over time. When I try to correct levels the reading start going all over the place, normally way higher than what it should using the reef calculators.

 

[Randy Holmes-Farley Verified Community Expert]

Which calculator? Which two part recipe (one is twice as potent as the other)

What did you enter for the solution name?

 

[jduong916]

I use recipe one (I'm pretty sure I used 1 lol). With the BRS calculator I input 2 part alkalinity (soda ash) and with the reef.diesyst.com I use randy's 2 part recipe 1.

 

[Randy Holmes-Farley Verified Community Expert]

I use recipe one (I'm pretty sure I used 1 lol). With the BRS calculator I input 2 part alkalinity (soda ash) and with the reef.diesyst.com I use randy's 2 part recipe 1.

Assuming you made it per directions, I can't see how it could be extra potent, but I'm not sure where the issue lies. Using the calculator, I get 67 mL to boost 135 gallons by 0.7 dKH. I'm not sure why you saw a large boost. It could be a combination of water volume estimation, testing errors both before and after, etc.

 

[jduong916]

Even if I used recipe 2 the readings are giving me more than double. I dose directly into the return pump section, do you think the alk solution could be mixing in the dt and not making its way down to the sump within that first hour? I'm actually leaning towards the test kits not being accurate or not enough time to have the alk solution fully mix within the tank.

 

[Randy Holmes-Farley Verified Community Expert]

I assumed the solution would mix in, but it may take longer than you think.

 

[TangingOut]

I would guess that your water volume is more likely around 110. Remember, manufacturer's tank volume is using outside dimensions. When I filled my 165 with a shallow sand bed and 100 lbs of rock, it only took a little over 110 gallons to start draining into the sump.

 

[jduong916]

Hmm lets see the math, 4' x 2' x 2' = 16 cubic ft = ~120 gallon --> 120 gallon x 22"/24" (water height) - 2 gallons (aquarium thickness approximate) = 108 gallons
40 gallon breeder = 3' x 1.5' x 1.5' = 6.75 cubic ft = ~50 gallon (nice didn't know that) -> 50 gallon x 16"/18" (water height) x 2/3 (% of sump used) - 1 gallon (aquarium glass) = 29 gallons
live rock in sump and display = maybe 15 gallon ( i assume three 5 gallon buckets if broken in pieces)

grand total = 108 + 29 - 15 = 122 gallons! You win, 110 is closer than my 135. I'll use 120 from now on

 

[SashimiTurtle]

I would guess that your water volume is more likely around 110. Remember, manufacturer's tank volume is using outside dimensions. When I filled my 165 with a shallow sand bed and 100 lbs of rock, it only took a little over 110 gallons to start draining into the sump.

Go check out a Red Sea tank dimentions and their advertised gallons, then plug in the tank dimentions in a calculator and you'll get a way different number. The red sea 650 peninsula is advertised at around 140 gallons but a tank calculator will have you at 160 gallons for those dimentions.

 

[jduong916]

Does that tank have an overflow. They could be accounting for the water height at that level giving a lower vilume of water.

 

[TangingOut]

Go check out a Red Sea tank dimentions and their advertised gallons, then plug in the tank dimentions in a calculator and you'll get a way different number. The red sea 650 peninsula is advertised at around 140 gallons but a tank calculator will have you at 160 gallons for those dimentions.

I think that's the only manufacturer l've seen so far using inside dimension to calculate tank volume.