# Perpetual Preservation System & Water changes



## Glouglou (Feb 21, 2006)

2 weeks going in this fertilizing method. Can it be true (coming fro PMDD) my plants look happy 

I was thinking at changing the 50% of water on a weekly basis, like 2 to 3 gallons every day to minimize the effect of one big change.

What do you think?

Are you really changing 50% or less?


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## AaronT (Apr 26, 2004)

I don't necessarily does any 'method' per say, but I'd say I do closer to PPS than any other method. I only do 25% or 30% water changes most weeks. So long as the nitrates and ammonia aren't builing up (the whole idea of PPS) you shoudl be fine with smaller less frequent water changes.


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## Edward (May 25, 2004)

Water changes of any frequency and any quantity do not have any effect on the continuous PPS dosing. You can change water any time you like. 
PPS is about supplying daily nutrients for each photoperiod in limits of luxury uptake.


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## Elkmor (Mar 30, 2005)

Edward said:


> Water changes of any frequency and any quantity do not have any effect on the continuous PPS dosing.


Why don't dose more after water change to achive target concentrations?


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## wiste (Feb 10, 2006)

A 50% water change is more affective than 5 - 10% water changes at reducing excess nutrients.
If you are overdosing ferts to prevent any nutrient deficiency, then you do not want to minimize the affect of the water change.
Changing 50% seems O.K. if you have a small aquarium. However, dumping several hundred gallons of water a week just does not seem ecologically friendly.


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## Edward (May 25, 2004)

Elkmor said:


> Why don't dose more after water change to achive target concentrations?


Your target is to supply what the plants need for the day.


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## Edward (May 25, 2004)

wiste said:


> A 50% water change is more affective than 5 - 10% water changes at reducing excess nutrients.
> If you are overdosing ferts to prevent any nutrient deficiency, then you do not want to minimize the affect of the water change.
> Changing 50% seems O.K. if you have a small aquarium. However, dumping several hundred gallons of water a week just does not seem ecologically friendly.


Well, you have two choices:

*PPS without water changes *and testing for NO3 and PO4 every two weeks or so

or

*PPS with 50% water changes* and no testing


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## Elkmor (Mar 30, 2005)

Edward said:


> Your target is to supply what the plants need for the day.


So, for plant there is no difference in DOUBLE difference in concentration of ANY nutrient? Say, Mg? Fe? K?


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## Edward (May 25, 2004)

Doubling already sufficient amount of nutrients will not make a significant visual difference.


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## Elkmor (Mar 30, 2005)

Say, I have 20 ppm of K, 5 ppm of Mg and 0.2 ppm of Fe.

After 50% water change (in bad case or in case of RO water) I'll have only 10 ppm of K, 2,5 ppm of Mg and 0.1 ppm of Fe. Is it normal? Will plant suffer from Mg defeciency? From K defeciency? I think that some species of plants will.


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## Edward (May 25, 2004)

Elkmor said:


> Say, I have 20 ppm of K, 5 ppm of Mg and 0.2 ppm of Fe.
> 
> After 50% water change (in bad case or in case of RO water) I'll have only 10 ppm of K, 2,5 ppm of Mg and 0.1 ppm of Fe. Is it normal? Will plant suffer from Mg defeciency? From K defeciency? I think that some species of plants will.


No they will not suffer from deficiency. They may have difficulties due to the sudden change.


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