NPT vs MPT classroom research

Just found out that donorschoose.org has completely funded my AP Chemistry research proposal. Basically, we will be setting up two identical 10G planted tanks in a window. One will have commercial planted substrate/fertilizer the other will be NP. They will have same number/types of plants and fish/snails in each. We will then observe plant/animal health/growth and do water analysis for the rest of the year. At the end, there will be a comparison report.

I plan to use Nerite snails, have 'plant packages' coming from a scientific supplier (20 different species or so), now I just have to decide on the fish species. I'm inclined to think of neon tetras/glowlight tetras due to their sensitivity to poor water conditions - but I want to avoid needing aquarium heaters since this is at school. So I'm considering killifish since they can handle a wider range of temperatures. It would also be interesting to see what happens to the fry due to the difference in natural/artificial fertilizers if there is a breeding cycle during the study. I don't have any experience with the killis though - so that is why I need you alls' input on this decision.

I've already got the two filters cycling in an established tank, and will be using water from it to fill these 10Gs. So there won't be a cycling period to deal with.

go with the perenial fish. ie killies, since i figure they could tolerate the direct sunlight better. but idk. mere speculation.

but im looking forward to hearing about your findings!!

i think your main problem will be trying to keep the temperature stable if trying to keep fish

what about mollies ?

What about the simplicity of guppies. They can tolerate a wide variety of temps. I have a bunch of them in my outdoor pond and I am amazed at some of the low and high temps they have lived through out there.

there ya go. lol. i figured it would be something simple as that.and now that i think of it, i recall seeing whole messes of mosquito fish living in stagnant ponds in apartment complex ponds and such. eh~

OK I may be a Fish Geek, nerd or Gerd, but I was thinking about your project and had these questions.

Is the window N,S,E or W facing? I'm just thinking about the possible temperature in summer.
OK I live in TX, but I'm certain having looked up Middle TN on NOAA that with a temp of 93F in the summer in the shade, a tank in direct South or West sunlight is going to bake. Guppies (preferred temp 79F), in fact most fish, during summer months with school closed and no A/C.
At the same time you are looking to have no heaters, but research shows that the low temps for 6 months of the year are about 30F in Nashville.

http://www.wunderground.com/NORMS/DisplayNORMS.asp?AirportCode=KBNA&SafeCityName=Nashville&StateCode=TN&Units=none&IATA=BNA

You don't want to have a heater in the tank, but.
I'm guessing the school will have some heating to prevent burst pipes, but even so, it's not going to be "tropical fish" warm. During winter do you wear warm clothes in class, because IMO I think if you can't wear T Shirts in class all year long, including first thing in the morning, it's going to be to cold for any tropical fish.

As for the plants, again, the temps will be what I would think would be artificially high to nature. There are members down here that keep some fish in outdoor tubs etc on their deck etc, they grow wonderfully, but this year with the temps getting high, have brought their fish indoors, to keep them cool, the plants aren't in direct sunlight / green house effect. What effect will this have on the plants compared to their normal aquatic environment?

Personally, I would have zero snails and zero fish. No fish, for the sake of the fish. No snails, because if one snail dies in the weeds and you do not see it, then the decomposing snail will affect the water, gradually adding possible nutrients for the plants, effectively altering the parameters of your "control" tank, or the "commercial" tank.

What do the other Box folks think?

yeti, i agree. as a scientist performing an experiment id want to control as many variables as i possibly could. doing experiments with live animals is difficult; not just for the sake of the animals used but more importantly the amount of sheer Randomness they add to the experiment.

try using test animals like triops or marbled crayfish! simple. low maintenance, highly tolerant to adverse conditions, and they reproduce parthigenetically. a perfect lab animal. although temps above 33*C will kill them if exposed for extended periods of time.

2sci: you say you're wanting to avoid aquarium heaters altogether? I'm not experienced with killifish, but don't they prefer a tropical environment?

I think that doing without heaters may be adding a level of variables to your results, because a lot of the plant packages may not be suitable for cooler temperatures.

Just a thought in planning your experiment.

i am wondering how much the grant was for,

The 'grant' was just the supplies being paid-for, ordered and delivered. The classroom stays within reasonable temperature parameters (I have three established bigger tanks in there. From Cichlids to Sunfish - no heaters other than their lights)

The window is NW facing and I will be keeping them out of full direct sun by using waxpaper as a light filter. My 10G tank at home in a West window does well with diffuse light through the blinds, temp only reaching 82F when it is 100F outside.

The plant shipment came in - and its less than impressive. So I've been pulling offshoots from plants in my established tanks to make up for it. The nerites have already been added for algae control.

You know what Whisper? I was eyeballing a nice shipment of guppies that the local petstore just got in and had the same thought. So I'm going to purchase a set of Orange ones for one tank and Blue ones for the other - stick with the school colors! Figure that the Freshmen Biology teachers could always use the offspring for genetics study later. (I've gotten half the department to at least set up goldfish tanks! Yippee!) The only 'bad' thing about guppies for this project is that they are SO TOLERANT of poor water conditions as compared to neons.

I'm now debating putting a few ghost shrimp into the mix to be the scavenger level of the biome. They've done very well and reproduced in one of my unheated betta tanks. And I know the shrimp will just fascinate the students to no end.

Pretty color guppies I think. If you ever need more let me know. I raise guppies also............I'm surprised the Bettas didn't eat the shrimp. LOL

Nope, have a tank full of ghost shrimp youngsters that 'appeared' in my flame orange betta's 10G. He might snack on a few - but doesn't get them all. Once they are big enough for me to see, he leaves them alone. Also have five 'algae eating shrimp' that I found at PetCo in there. They look like half-sized bamboo shrimp.
That tank has gotten so full of the ghosts that you see them swimming back and forth - sometimes bumping right into Sunstreaker!

I've started adding ghost shrimp to every betta tank now. If they don't bother them - I'll add some of the red cherry shrimp that I just won on aquabid when they come in.

Hmmm, on second thought - since I won 30 red cherries - I think I'll put a handful of them into each of these research tanks. Students will really notice shrimp that appear 'cooked'....

Just got the materials for the sponge filtration in. Had to pull out the power filters I had originally wanted to use for this - because the currents were too strong.

So here the two tanks are - with just plants/nerites. The guppies start going in this week - after the students hook up the sponge filters tomorrow. You'll notice that I've wrapped the tanks in bubble wrap to insulate them from solar heating while still allowing light in. There are 25W of light per tank - I'm using daylight reptile bulbs in the hoods. (Have had a LOT of success with these bulbs in my small home planted tanks)

Have a mix of over a dozen different species of plants/aquatic moss in each tank. All are easy-to-moderate in difficulty - none need extra CO2. Tried to arrange them to be as identical as possible. Only decorations are some polished river rocks in the front.

Since I have 30 red cherry shrimp coming in, I'll be putting a handful of each into these two tanks instead of ghosts.

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nice setup! Do you think it's possible that the placement of the tanks where MPT is in full window exposure and NPT has about 30% shade by the window frame/wall is going to make a difference? I just noticed that and was curious if that would make any impact of the amount of natural light that tank will receive. In the close up photo it's almost as if that corner is going to be shaded pretty well by the wall, which might affect plant growth.

Very nice setup for research! Be sure to keep us posted on the results as you go.

Update: Students now know the nitrogen cycle, how it relates to the bubble filter and the water circulation it creates. They are fascinated by the pregnant guppies and cherry shrimps. They've done water tests twice per week.

Many have signed up to 'adopt' the expected excess of guppies in April (after research project is complete). Several have never 'had their own pet' and like the idea that small tanks are allowed in dorm rooms (most are seniors). Don't worry guys - these students will know more about fish keeping than the average fish owner before this project is complete. So the adopted guppies will be in good hands!

We've had a green water/bacterial bloom in the MPT tank. Noticed that it coincided with a spike in phosphates. (most likely caused by the use of 'pH down' - phosphoric acid). They learned how to use a three day blackout + UV filter to control this problem. Coincidently, it also 'solved' the problem of string algae in that tank as well.

The NPT tank is having a string algae outbreak right now. It is covering the leaves of the Java Ferns. Will probably start a three-day blackout on monday to slow it down and allow the nerites and cherry shrimp to mow it back.


We've found that pH levels have jumped from 7.2 to 7.8 - especially in the NPT. Most likely cause is the spike in oxygen levels caused by the rapid growth of the string algae. The interesting thing was that the levels plumeted after a five day period of heavy clouds/rain - even with the timed artificial lighting. Made for an interesting conversation. Will be adding more chemical buffers to the MPT system on Monday.

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Another update: Even though the plants and water came from the same sources, each tank showed distinctly different algae issues.

The MPT had green water issues for 6 weeks - water tests showed spikes in phosphate levels. It has since remediated itself even with the higher phosphates with the duckweed showing explosive growth. Phosphates originated from commercial fertilizer and pH buffer. We will be formulating our own fertilizer in the next few weeks - minus any phosphates.
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On the other hand, the NPT is having major issues with string algae. As per the Walsted guidelines, we've been 'harvesting by hand' as much of the pest algae as possible. (And weighing it to add to final biomass calculations) Many of the plants have been killed off by the algae and the duckweed is barely hanging on. Suspect a very low nutrient level in this tank. Am debating going with the other Walsted guideline and adding a ton of emergent plants to the tank - providing I can find a donated source of these. (I'll add the same species/amounts to other tank)


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Guppies have been breeding profusely, though each tank has lost the biggest-tailed male and biggest female (after giving birth). Suspect that these were the older guppies at purchase. Cherry shrimp have also done well and females carrying eggs have been spotted. The nerites (of course) have also been contentedly eating their way around each tank.

The temps only went into the low 60's for a week, since the weather turned cold and the school was replacing old boiler towers with brandnew ones. Since the new ones came on line, classroom temps have been in the upper 70s to low 80s every day. Wonderful for the fish - hard on our tempers! The bubblewrap insulation around tanks has been highly successful in mitigating solar heating of any kind.