The problem, as I see it, is the small linear accumulation of profits, but the geometric accumulation of liabilities.
for example, if the grid was:
1.7
1.6
1.5
1.4
1.3
a:if you have a buy/sell at 1.5.
b: then market moves to 1.6.
(at this point, you close out the long for +100. but, immediately open another buy/sell.
you have encashed 100 pips, but have 2 open sells, and new open buy. net gain zero)
c: market moves back down to 1.5.
(you now close out the sell (opened at 1.6) for +100. theoretically, you should open another buy/sell.
but, you now have +200 pips in the bank, an open buy at 1.6 (-100), nett 100 pips.
but....
a: if the market moves from 1.5 to 1.6
(you cash the 100 pips, and open another buy/sell)
b: market moves to 1.7
(you cash another 100 pips from the buy, an open another buy/sell.
you have cashed out 200 pips, but have a sell from 1.5 (-200) and a sell from 1.6 (-100), nett exposure -300)
c: market moves to 1.8.
(you cash the buy for another 100 (nett banked 300 pips), but are required to open another buy/sell.
you have liabilities of -600! -300 from 1.5, -200 from 1.6 and another -100 from 1.7.)
The nett result is a linear growth, but geometric liability.
However, grids are recognised as being based on the assumption of reversion to mean.
That is, money is made by riding out stomach-churning losses until the reversion kicks in. It is acknowledged that a strong trend will eventually break the grid. But, even if the grid reverts, depending on the time it takes to revert, the "notional" return to zero is at a cost of interest payments, etc, while the trade has been underwater. So, in truth, it is actually a small loss.
However, if the grid spacings are wide enough, you can ride out a bigger trend. But these trades will logically last longer, and the cost of the trade is expensive as you have to pay to keep it open longer while it returns.
I am still convinced there is a way out of this. I am determined to find a viable mechanism.
One note is that there appear to be some variations on the grid system.
Since the principle is based on not closing out a position, and essentially to aggregate them over time, why not adapt the principle of "not closing out a position" to any indicator based system?
For example, any old MA-X-over system could be used to trigger buys and sells. You close out any winning position to bank profits, and leave any losing positions open until they return to median to close out,
OR, close out an open long and sell when their aggregate is zero?? (eg, if a losing buy is -620, close out this when an open sell can be matched against it when the price reaches -310, an aggregate of zero.) This might reduce time of open losing positions and the resultant trading costs, as well as free up margin more quickly.
This way a bias is introduced into the trading.
Additionally, in order to avoid positions to be opened too close together, ie, when market is in chop-mode, you refuse any new trade unless it is greater than a defined "grid" size. eg, if the market is choppy, and you open a trade, either buy or sell, and you have a grid size of 100, you refuse any new buy/sells unless they are at least 100 pips away. This avoids collecting a heavy position at a narrow price range.
This is a possible variation on grid-trading; just leave positions open.
The advantages are the addition of a bias, the principle of leaving positions open as per grids.
Being a trend-follower, my mindset is to wait for the one-directional trend, which is the money-maker, whereas grids fear the trend, as it kills them in one single shot.