Question
QUESTION: basically, if I have high pH, Do I add sodium bicarbonate?   Lo pH, Do I add muriatic acid?

ANSWER: Dear Jana,

Thank you for your question.
Sodium bicarbonate can be added to the pond as a simple solution for raising the pH balance of water.
The pond chemical sold as pH down is sulfuric acid and is also available in different types.
Please note that when you are not common with this you can best use products available in the pondshops as there is a large risk to is.
When PH fluctuates to much or is raised or lowered to much it will harm or even kill the fish!
Best way is to go adjust it bit by bit.
Also in time a pond should be in most cases almost selfregulating (fluctuations can be when there is large amounts of rain or new water is added, etc).

Good luck and do not hesitate for further assistance.

Kind regards,
Raf

---------- FOLLOW-UP ----------

QUESTION: Last year my pond developed lots of string algae.  It even interferred with my pumps.  I have a little more than 10,000 gals, 3 submersible pumps and 1 above ground (long story, don't ask). I have plenty of water circulation.  The algae is starting.  It is very stressful to me.  I enjoy the clear water so much.  I have a 3x3x3 waterfall with 5 filter-filled bags for filtration.  I made my own skimmer, (it had to be in the middle, because it is a slope sided gunnite pond.  It is under 4 pine trees, 1 birch, 1 redbud, 1 black walnut tree.  (very messy).  To be honest, I'm trying to keep my costs down.  Trying to find more economical chemicals to use.  Last year pH down didn't even faze it.  I have 4 2 year old Koi, 1 1 year old Koi, and 2 small babies that I just bought.  (I also have a snake that is frequently visiting and have ordered a snake trap.)
Thanks for listening.

Answer
Dear Jana,

Unfortunately Ph is indeed very important, however not vital for controlling Algae.
Algae comes in to the pond due to dissolved waste and sun.
As waste turns in to (finally) nitrate it becomes ideal for algae to grow.
Especially with sun.
I tend to get rid of algae with flushing, every week we flush the pond for approximate 10% and refill it with clear tabwater.
Also we, koi owners, use in the most cases A UV lamp in approximate 3 watts per 1000 Liters.
This together with a large filter, and for this issue a plant filter or at least lots of plants in the pond will ensure clear water.
In short:
Waste comes in to the pond due to the fish, plants surroundings.
We need to get rid of this the quickest way.
Most of us use a pondfilter that has a PRE filter to get rid of the visual debris, then a biological filter to reduce the dissolved waste from ammonia to nitrate, then we flush and handle the nitrate by having larger plantfilters.

Hope this helps.
Good luck and happy pondkeeping.
Regards,
Raf