# How does one assess/determine....



## Cynthia L-F (Mar 3, 2005)

I'm working on completing the "Water parameters template" and wonder if there is some calculation to determine plant mass? It can be very subjective. I used to think I had heavy planting until I started checking the photos of aquascapes on-line.

Also what does "TDS"" stand for? It does not appear to be listed in the glossary.

And while I have your attention or should I ask this elsewhere? If I change 25% of H2O weekly can the tank carry a higher fish load.? And I am correct in thinking that the fish load is determined by the inches of fish relative to the # of gallons in the tank?

(confused) cynthial-f


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## gnatster (Mar 6, 2004)

TDS means Total Dissolved Solids, typically taken with a meter and sometimes also noted as uS. It's a nice item to know, but don't worry if you do not have the measurement, the template has some flexibility. 

I've also added it to the Acronym Glossary, thanks for pointing it out.


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## JanS (Apr 14, 2004)

Cynthia L-F said:


> If I change 25% of H2O weekly can the tank carry a higher fish load.? And I am correct in thinking that the fish load is determined by the inches of fish relative to the # of gallons in the tank?
> (confused) cynthial-f


I change a minimum of 25% weekly even on tanks with light fish loads. The best way to figure it out is to just keep an eye on your nitrates. If it creeps above 20 ppm, you need to step up the changes.
The fish load is very variable. If they are small fish, with a small body mass, you can add quite a few. If you're looking at something that's larger with a body as high as it is long, you wouldn't be able to add more than a couple more (depending on what you already have in the tank).

It would be helpful to know what size tank you have, what your current inhabitants are, and your water parameters are to better answer that question.


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## Cynthia L-F (Mar 3, 2005)

Let's see if I can get this right. I have a 55 g tank which is currently inhabited by 6 Lemon Tetras, 2 Rasboras, 4 Zebra Danios, 4 Cory Cats, 5 Otos, 3 Platys and 4 pairs of Rainbows. pH is 6.8, KH 4, GH 8, zero Nitrates, CO2 19(Set at 2 bubbles per second). Phosphates, magnesium and Calcium levels are unknown. WPG is .6 (90 watts total, I have a new light system on order). Plants are:Ludwigia Repens, Dwarf swordplants, Echinodorus blehri, cryptocoryne, Anubias nana and barteri, Giant Ambulia and a glosso I planted Monday which by Thursday had no leaves and is just a small round of bare stems. :???: 
Thanks,
cynthia


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## glenhead (Jan 29, 2005)

Fish load is dependent on your plant/critter balance and your level of fanaticism in doing water changes. I'm pretty fanatic - do 25-30% water changes most weeks (missed this last weekend). My tank has just recently reached the point where my nitrates are going down if I don't supplement the plants' usage. The "industry standard" is one fish-inch per gallon of water. That means an inch of a fairly streamlined fish - one full-grown Lemon Tetra inch is a heckuva lot less than one full-grown Oscar inch. I carry a full-grown load of just under 2 fish-inches per gallon. Most of my fish (except the Siamese Algae Eaters) are pretty well full grown. At the risk of boring people, here are the specs, flora and fauna in my tank:

55 gallons, 2 inches of cheap-o aquarium gravel, 110W CF lights on 13 hours per day, DIY dual-2-liter CO2 feeding Hagen ladder, supplement with PMDD and Excel, bubble wall along the back of the tank (my wife likes the look). pH stays at 6.5-6.6, kH about 0.75, gH about 5, ammonia and nitrites zero (of course), nitrates supplemented to 10ppm (else they drop 2ppm/week), phosphate 0.5-1ppm, temp kept at 78-79F.

Plants:
_Cabomba caroliniana_: 10-15 stems, grows like a bad weed
_Vallisneria spiralis_: 5 small clumps, not doing too well
_Ceratopteris thalictroides_: One huge plant - a foot+ in diameter, 18" tall, out of control
Java Moss: Two wads, total about softball-sized, started three months ago as two walnut-sized clumps
Giant Hairgrass: A few small clumps, just starting to do well
Dwarf Hairgrass: 15-18 plugs, just starting to spread
_Ludwigia repens_: 10-12 stems, going to have to thin them severely, grow 2-3 inches a week
_Alternanthera reineckii 'roseafolia'_ Just separated into 8 stems, healthy, but not growing very fast
Red Tiger Lotus: one bulb, just starting
Green Tiger Lotus: same as red
Dwarf _Nymphaea stellata_: very dense
Pennywort (_Hydrocotyle leucocephala_): One stem so far, needs trimming - has grown over a foot in the last two weeks
Hornwort: Floatie, constantly trimming
_Bacopa caroliniana_: 3 stems, have shot up six inches in the last two weeks (this is slow growing???)
Various unidentified "mixed group" stem plants (gotta upload some pics for ID!)

Critters: One Dwarf Gourami, 7 Lemon Tetras, 7 Glowlight Tetras, 6 Black Neon Tetras, 11 Cardinal Tetras, 3 Long-finned Blue Danios, 3 Otos, 4 _Corydoras leucomelas_, 3 Panda Corys, 2 Golden Rams, 3 SAEs, several pond snails, several Maylaysian snails. This equates to 83 fish-inches (plus snails), in under 50 actual gallons of water. The plants and snails keep the substrate pretty clean, and everything is very stable.

If your nitrates stay at zero, your plants and water-change regimen are using all the output of the fish, so you don't have too many fish from a bioload perspective. I keep seeing that some fish are stressed by physical crowding (they need their space), but careful species choice can avoid that somewhat. I don't see it in my tank. Keep a close eye on your nitrates, check your ammonia and nitrites for a few days after you add fish, change more water if parameters change.

Standard disclaimers here, your mileage may vary, etc etc blah blah blah. ;-)

HTH


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