darkangel Posted February 23, 2009 Report Share Posted February 23, 2009 I have re-vamped my 72 a little while back which turns out to be a 75, (48Lx18Wx20H). In theory this tank is 75 gal. Now, on a technical side of things. With the internal space consumption and displacement of water volume from substrate, driftwood, rocks etc. this tank now only holds 56.5 gallons of water (yes I counted them). When calculating dosage of fertilizers, water treatment (prime), buffers, meds etc. and calculating lighting in watts per gal, kelvins, lumens and so on, Would this be calculated for a 75 gal. or a 56 gal. Get your brains in high gear, I want to hear what everyone comes up with (theory or technical). Quote Link to comment Share on other sites More sharing options...
catshanon Posted February 23, 2009 Report Share Posted February 23, 2009 I would say do the calculations for 56.5Gallons.. I am intrigued though, how did you get an exact measurement of 56.5G ??? Raj Quote Link to comment Share on other sites More sharing options...
darkangel Posted February 23, 2009 Author Report Share Posted February 23, 2009 I would say do the calculations for 56.5Gallons.. I am intrigued though, how did you get an exact measurement of 56.5G ??? Raj Tank was completely empty. After adding the 2 - 5 gal pails of water that I did a good gravel sweep on the tank before emptying it. Added substrate, driftwood, rocks and plants. I then began filling the tank with 5 gal pails, (also marked the 5 gal point in the pail). It took 9 additional 5 gal pails & 1.5 - 1 gal pails (us gal) and that brings the water level just to the bottom of the center crossbrace. I only went through the trouble to find out exactly how much water the tank had in it. Quote Link to comment Share on other sites More sharing options...
soliver Posted February 23, 2009 Report Share Posted February 23, 2009 I would measure the fertilizer, buffer,meds and prime for the 56 gallons but the lights for the 75. Light calculations have to due with the depth of the tank. although the tank is holding less water, it still has the same depth. Quote Link to comment Share on other sites More sharing options...
catshanon Posted February 23, 2009 Report Share Posted February 23, 2009 Light calculations have to due with the depth of the tank. although the tank is holding less water, it still has the same depth. That would depend on the thickness of the gravel. If there is a 2" layer, then the light has to penetrate a shallower depth. (IMO)... Also, Darkangel, do you really do such meticulous calculations when dosing prime or fertilizers ? medicine is a different story, but I kind of take it easy with my tank's maintenance.. I always put in an approximate amount(on the lower side) of prime and I am erratic with my ferts dosing regime.. I like the tank to take its own course... but thats me..and people are different.. Quote Link to comment Share on other sites More sharing options...
werner Posted February 24, 2009 Report Share Posted February 24, 2009 Just 'cause I want to play devil's advocate: What about the little spaces in between the gravel? Was the driftwood previously waterlogged or dry? At what rate will your plants be photosynthesizing (they use water for this.) Also as your plants and fish grow, the added mass will displace more water... :smokey: Quote Link to comment Share on other sites More sharing options...
patrick Posted February 24, 2009 Report Share Posted February 24, 2009 Just 'cause I want to play devil's advocate:What about the little spaces in between the gravel? Was the driftwood previously waterlogged or dry? At what rate will your plants be photosynthesizing (they use water for this.) Also as your plants and fish grow, the added mass will displace more water... :smokey: Let's not forget filters, an FX-5 for example, holds alot of water Quote Link to comment Share on other sites More sharing options...
digital-monk Posted February 24, 2009 Report Share Posted February 24, 2009 I don't think that a lot of the measurements for Prime and even some med's are "exact". For example Prime will work very differently in water with Chlorine than Chloramine, and the bottle just says double the dosage. That doesn't sound 'exact' to me. Also if there's higher levels of Ammonia and Nitrites the Prime will react with that. My answer isn't very technical, but I think it's not an exact chemical lab experiment that we're trying to achieve here. It's definately food for thought though. Quote Link to comment Share on other sites More sharing options...
jvision Posted February 24, 2009 Report Share Posted February 24, 2009 If you're dosing your ferts via EI, I don't think it really matters since the whole idea is to overdose anyway. And, if you're not using EI, you're probably using test kits... then it doesn't matter tank volume b/c you'd be aiming for a specific ppm. For light, I'd probably go w. 75 gal, too. Lighting is generally based on SIZE of tank, and not VOLUME of water. Quote Link to comment Share on other sites More sharing options...
soliver Posted February 24, 2009 Report Share Posted February 24, 2009 (edited) For light, I'd probably go w. 75 gal, too. Lighting is generally based on SIZE of tank, and not VOLUME of water. At least i got one part right Edited February 24, 2009 by soliver Quote Link to comment Share on other sites More sharing options...
corrosionjerry Posted February 24, 2009 Report Share Posted February 24, 2009 I believe in the keep it simple theory: adjust the ferts when you see a problem with the plants maintain good lighting and treat the water with prime for the amount of water that you know is going in the tank.... that will be close enough.... Quote Link to comment Share on other sites More sharing options...
darkangel Posted February 25, 2009 Author Report Share Posted February 25, 2009 WOW. Lots of brain activity on a Monday. What nobody parties anymore? Jerry, Your the only one that waited til Tuesday. Ok guys I'm not that anal about this I just did it to have some fun, I have nothing better to do with my time while I wait for a guy in a green suit & mask with a knife to mug me. I calculate everything for 75 gallons. Thanks for the replies, All of them were very good. Quote Link to comment Share on other sites More sharing options...
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