Estimating overall water volume. Does this seem right?

madweazl · Feb 11, 2019

That calculator guesstimated our total volume at 72 gallons (75g display with 30g sump). Through dosing over time, we figured it to be 74g; pretty dang close for us.

Philipgonzales3 · Feb 11, 2019

madweazl said:
That calculator guesstimated our total volume at 72 gallons (75g display with 30g sump). Through dosing over time, we figured it to be 74g; pretty dang close for us.

You must have two gallons in your plumbing! I'll just have to find a plumbing volume calculator that you enter your length, diamter, and pump, along with any connectors, etc.. jkjk

Haha sounds close enough. Thanks! Pretty confident in it then. May help some other ppl out. I'm all for working smarter and using online calculators and then of course checking for expected results after. Just as a general idea, not even just related to tanks.

Even Further · Feb 11, 2019

For accurate volume, use the inside measurement of the tank, with the normal water level.

radiata · Feb 12, 2019

Philipgonzales3: Getting back to calculators, thanks again for the help locating those other calculators...

I've been wondering this for a while now (years, in fact). If one knows the Specific Gravity of an unknown volume of water, couldn't one add 5 gallons of RO/DI water (1.000 SG), test the SG again, and back into a calculation of the total unknown volume?

I think I once read, way back when, that people with ponds use something like this to calculate the actual volume of their ponds.

Philipgonzales3 · Feb 12, 2019

radiata said:
Philipgonzales3: Getting back to calculators, thanks again for the help locating those other calculators...

I've been wondering this for a while now (years, in fact). If one knows the Specific Gravity of an unknown volume of water, couldn't one add 5 gallons of RO/DI water (1.000 SG), test the SG again, and back into a calculation of the total unknown volume?

I think I once read, way back when, that people with ponds use something like this to calculate the actual volume of their ponds.

Hmm, that's a good idea except I would be afraid to modify the specific gravity of my aquarium by too much at once. But I guess the same pricinipal may work with a couple of gallons. For now this will have to do. I'm sure there are other ways, such as @madweazl mentioned they calculated by dosing.

I'm thinking it may be easier to do this calculation with something that we have a higher resolution to test for such as magnesium or calcium. Maybe @madweazl will share the basic idea of calculating water volume by dosing?

vetteguy53081 · Feb 13, 2019

When treating and dosing, use the USEABLE gallons in the tank. A 50 g with rock and décor will have 43 useable gallons. I don't count the sump

madweazl · Feb 13, 2019

vetteguy53081 said:
When treating and dosing, use the USEABLE gallons in the tank. A 50 g with rock and décor will have 43 usable gallons. I don't count the sump

Actually, you want to dose the total volume of water. Scenario:

75g tank with sump - total volume 74g
75g tank with sump - "usable" gallons 67g (I just used your delta of 7g)
Current alkalinity 7.5 dKh - desire alkalinity 8.0 dKh

74g (actual volume) requires 26.4ml of soda ash - tanks alkalinity now 8.0 dKh
67g ("usable" volume) requires 23.9ml of soda ash - tanks alkalinity now 7.95 dKh

If you continue doing this, your parameters will stray further and further from your desired levels.

jtl · Feb 13, 2019

I simple took the inside water dimensions and subtracted the approximate size of my rock. I measured the dt and the sump. My dt is advertised to be 100g but in reality it is 87.5g empty, my sump is 51g empty. By the time I allow for sand, rock equipment room in the sump for draw down water I am at roughly 100 gallons of water.

jtl · Feb 13, 2019

OP, I am surprised that your Ca is so low using IO. Fwiw, I did not like Fritz salt, the Mg was way high for my liking. Something like 1700-1800.

Jet Sled · Feb 13, 2019

Im fairly new myself, but Ill share with you what has been working for me so take it with a grain of salt! I am using Reef Crystals and I have kept my Alk at 9 consistently for the past two months or so (10-20 nitrates). Ive had great growth on everything and have not lost a single coral. I have about 30+ frags SPS, torches, hammer, frogspawn, zoa's etc.. all kinds of stuff in my tank and they use about half a point per day .5 of alk currently.

I did not start dosing until I tested so much I could actually start to see my levels dropping and I already had about 20 frags in my tank at this point. I dont pay much attention to my calcium tbh, so I focus mostly on my alk. I figured the two part will level everything out as long as I keep my alk stable. Once I figured out how much my tank was using per day I started dosing to keep it at levels that I wanted and was easy to know how much to add. I would skip dose days and test just to see how it effected the tank. I now dose daily and test my alk q other day and everything else weekly.

I would say you could dose to get your levels where you want them, but stop and monitor them from there through consistent daily testing and see how the water changes effect your levels all prior to introducing a two part. All the testing and you will become a pro and feel better in tune with your tank at least this has been my experience. I have literally burned through almost a full bottle of Red Sea Alk reagent in two months, but I feel way more comfortable with how my tank reacts now, so have started testing less than I did before. I also noticed that keeping my salinity at 1.026 helps keep my Calcium/Mag at the levels I desire.

Go grab a bunch of cheap 10 dollar frags from your LFS or if you have a local FB reef group ask around to see if anyone will hook you up with some cheap frags. Lots of people love helping others and you could get stuff really cheap if not free! I was given free frags and in the future plan to pay it forward myself.

Flameback Pair · Feb 14, 2019

Here is a R2R article about determining actual water volume:

https://www.reef2reef.com/ams/beginner-series-1-what-is-your-actual-water-volume.574/

It compares concentration of Calcium ions before and after an addition of Calcium supplementation. A little bit of math but more accurate calculation.

Philipgonzales3 · Feb 14, 2019

jtl said:
OP, I am surprised that your Ca is so low using IO. Fwiw, I did not like Fritz salt, the Mg was way high for my liking. Something like 1700-1800.

I'm having a little bit of inconistencies with my calcium readings. API put me at 320 today. Did the red sea test and got 380, 430, then 390. I feel like I did all 3 tests the same. The only thing I can think of is either the 430 result I had a little bit of air in the syringe. The 380 and 390 seem to be more consistant with what I should be expecting. Here are my results from today.

madweazl · Feb 15, 2019

There should always be air in the syringe, it is created by the volume added with the little plastic tip that you install on the syringe and doesn't affect your test results (take your reading where the plunger is, not the liquid in the syringe).