# [Wet Thumb Forum]-Query about the Sears and Collins paper



## Ben C (Apr 16, 2006)

Hey, 

reading the Sears and Collins paper again.. i'm a little confused about something. In the "recommendations" section, its says that K2SO4 should be added until nitrates reach 2ppm or less. Then add KNO3 to bring the nitrates upto 3-5ppm. 
why is this? why reduce the nitrates only to increase them again? If you could explain this to me, i might be able to sleep tonight!!

thanks, 

BEN


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## Ben C (Apr 16, 2006)

Hey, 

reading the Sears and Collins paper again.. i'm a little confused about something. In the "recommendations" section, its says that K2SO4 should be added until nitrates reach 2ppm or less. Then add KNO3 to bring the nitrates upto 3-5ppm. 
why is this? why reduce the nitrates only to increase them again? If you could explain this to me, i might be able to sleep tonight!!

thanks, 

BEN


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## imported_BSS (Apr 14, 2004)

It's been a long time since I've read their paper, but I think some of their recommendations are a bit dated. My chemistry courses are even farther back in history, but I don't see how adding K2SO4 should affect the NO3 levels. I add K2SO4 to increase my K+ levels. Some come from the KNO3, but the rest is supplemented with K2SO4. If the K in KNO3 separates, I wouldn't think the K2SO4 would affect the NO3 level.

If others know better, please correct me!
Brian.


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## Roger Miller (Jun 19, 2004)

The idea was that adding K2SO4 would lift the potassium limitation on plant growth. The accelerated growth rate would cause nitrate levels to drop.

I can only think of one reason why Sears and Conlin (not Collins) would wait for NO3 to drop before adding KNO3. They were building a step-by-step method and separated the nitrate additions into a separate step from the initial potassium additions.

Sears and Conlin is a little dated now and I have always regarded it as a flawed approach. Despite that it is a mistake to overlook the very important contributions that the paper made to aquarium keeping. I understand (from Art Giacosa) that the basic idea that Sears and Conlin described was around for some time, but Sears and Conlin popularized the method as a systematic and relatively easy-to-follow procedure. Most of the "methods" that followed Sears and Conlin have built on their accomplishments.


Roger Miller


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## imported_BSS (Apr 14, 2004)

That makes sense. And no doubt about the papers contributions to the hobby. I just meant to imply that approaches had evolved quite a bit from their early ideas.


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## TWood (Dec 9, 2004)

The Sears-Conlin paper was the first widely read hobbyist-level approach that talked about actually controlling certain parameters. Which is a good thing. The bad thing was that it spawned an obsession with test kits. It also didn't help when Mullins came out with a different batch mix (300 ml versus 500 ml) that nobody seemed to pick up on until they were both confuzzled together. It always seemed unnecessarily complicated to me.

I think I was one of the first ones that asked Chuck Gadd if I could just enter '1' as the number of milliliters of water in the batch solution in his calculator so I could just dose dry chemicals. Now that approach has evolved into The Fertilator:

http://www.aquaticplantcentral.com/forum/fertilator.php

TW


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## Ben C (Apr 16, 2006)

Hey,

thanks for the replies.. (i knew it was Conlin! d'oh! it was about 00:30 when i wrote that message!!) 
The replies seem to make sense. I got the feeling myself that things had moved on since the paper, and was wondering if there was a more recent paper anywhere that i might read? 
I managed (eventually) to find some Epsom Salts here the other day, and have a funny story which i'll post later!
thanks for your help, 

BEN


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## ROSS (Oct 8, 2003)

was there a more recent paper that we might read?

Ross
sitting at home bored with no work to do!!!


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## Roger Miller (Jun 19, 2004)

Try this

http://www.aquatic-plants.org/est_index1.html

I don't endorse this (or any other) method. There's nothing you can do to make me, so don't try









There are scads of other methods that have been written up in various forums at various times. Tom's method is just the latest and not necessarily greatest in the progression.

Roger Miller


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## TWood (Dec 9, 2004)

Or ignore that and read the levels suggested here:

http://www.sfbaaps.com/reference/barr_02_02.shtml

Then use PO4 and NO3 test kits once a week after the water change, and this to get the levels right:

http://www.aquaticplantcentral.com/forum/fertilator.php

I use pale new growth on h. difformis as an indicator for iron (Fe) to dose CSM+B for Fe at 0.1 ppm as needed. (About once a week seems to do it in my tanks.) I dose potassium (K) at about 5ppm a week, or more if NO3 doesn't drop during the week.

This really doesn't have to be rocket science, but I know it's fun to make it out to be so.

TW


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## ROSS (Oct 8, 2003)

Sorry for butting in!!

Many thanks to the helpfull crowd


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